diff --git a/content/canvas/src/CanvasRenderingContext2D.cpp b/content/canvas/src/CanvasRenderingContext2D.cpp
index d58c13f5f0f5..66be67f3b5d8 100644
--- a/content/canvas/src/CanvasRenderingContext2D.cpp
+++ b/content/canvas/src/CanvasRenderingContext2D.cpp
@@ -4080,7 +4080,7 @@ CanvasRenderingContext2D::MarkContextClean()
 bool
 CanvasRenderingContext2D::ShouldForceInactiveLayer(LayerManager *aManager)
 {
-  return !aManager->CanUseCanvasLayerForSize(gfxIntSize(mWidth, mHeight));
+  return !aManager->CanUseCanvasLayerForSize(IntSize(mWidth, mHeight));
 }
 
 }
diff --git a/content/media/MediaDecoderReader.cpp b/content/media/MediaDecoderReader.cpp
index 8baeefd4587e..346e4d4ceb63 100644
--- a/content/media/MediaDecoderReader.cpp
+++ b/content/media/MediaDecoderReader.cpp
@@ -18,6 +18,7 @@
 
 namespace mozilla {
 
+using namespace mozilla::gfx;
 using layers::ImageContainer;
 using layers::PlanarYCbCrImage;
 using layers::PlanarYCbCrData;
@@ -242,18 +243,18 @@ VideoData* VideoData::Create(VideoInfo& aInfo,
 
   PlanarYCbCrData data;
   data.mYChannel = Y.mData + Y.mOffset;
-  data.mYSize = gfxIntSize(Y.mWidth, Y.mHeight);
+  data.mYSize = IntSize(Y.mWidth, Y.mHeight);
   data.mYStride = Y.mStride;
   data.mYSkip = Y.mSkip;
   data.mCbChannel = Cb.mData + Cb.mOffset;
   data.mCrChannel = Cr.mData + Cr.mOffset;
-  data.mCbCrSize = gfxIntSize(Cb.mWidth, Cb.mHeight);
+  data.mCbCrSize = IntSize(Cb.mWidth, Cb.mHeight);
   data.mCbCrStride = Cb.mStride;
   data.mCbSkip = Cb.mSkip;
   data.mCrSkip = Cr.mSkip;
   data.mPicX = aPicture.x;
   data.mPicY = aPicture.y;
-  data.mPicSize = gfxIntSize(aPicture.width, aPicture.height);
+  data.mPicSize = aPicture.Size().ToIntSize();
   data.mStereoMode = aInfo.mStereoMode;
 
   videoImage->SetDelayedConversion(true);
@@ -373,7 +374,7 @@ VideoData* VideoData::Create(VideoInfo& aInfo,
   GrallocImage* videoImage = static_cast<GrallocImage*>(v->mImage.get());
   GrallocImage::GrallocData data;
 
-  data.mPicSize = gfxIntSize(aPicture.width, aPicture.height);
+  data.mPicSize = aPicture.Size().ToIntSize();
   data.mGraphicBuffer = aBuffer;
 
   videoImage->SetData(data);
diff --git a/content/media/MediaStreamGraph.cpp b/content/media/MediaStreamGraph.cpp
index db8fd8c577c3..8090f717cfa9 100644
--- a/content/media/MediaStreamGraph.cpp
+++ b/content/media/MediaStreamGraph.cpp
@@ -27,6 +27,7 @@
 
 using namespace mozilla::layers;
 using namespace mozilla::dom;
+using namespace mozilla::gfx;
 
 namespace mozilla {
 
@@ -895,7 +896,7 @@ SetImageToBlackPixel(PlanarYCbCrImage* aImage)
   data.mCbChannel = blackPixel + 1;
   data.mCrChannel = blackPixel + 2;
   data.mYStride = data.mCbCrStride = 1;
-  data.mPicSize = data.mYSize = data.mCbCrSize = gfxIntSize(1, 1);
+  data.mPicSize = data.mYSize = data.mCbCrSize = IntSize(1, 1);
   aImage->SetData(data);
 }
 
diff --git a/content/media/omx/OmxDecoder.cpp b/content/media/omx/OmxDecoder.cpp
index 1d53cde4f766..2de1b34a8e97 100644
--- a/content/media/omx/OmxDecoder.cpp
+++ b/content/media/omx/OmxDecoder.cpp
@@ -38,6 +38,7 @@ PRLogModuleInfo *gOmxDecoderLog;
 
 using namespace MPAPI;
 using namespace mozilla;
+using namespace mozilla::gfx;
 
 namespace mozilla {
 
@@ -828,7 +829,7 @@ bool OmxDecoder::ReadVideo(VideoFrame *aFrame, int64_t aTimeUs,
       // GraphicBuffer's size and actual video size is different.
       // See Bug 850566.
       mozilla::layers::SurfaceDescriptorGralloc newDescriptor = descriptor->get_SurfaceDescriptorGralloc();
-      newDescriptor.size() = nsIntSize(mVideoWidth, mVideoHeight);
+      newDescriptor.size() = IntSize(mVideoWidth, mVideoHeight);
 
       mozilla::layers::SurfaceDescriptor descWrapper(newDescriptor);
       aFrame->mGraphicBuffer = new mozilla::layers::VideoGraphicBuffer(this, mVideoBuffer, descWrapper);
diff --git a/content/media/plugins/MediaPluginReader.cpp b/content/media/plugins/MediaPluginReader.cpp
index 7f14dfce5af2..26435b47650a 100644
--- a/content/media/plugins/MediaPluginReader.cpp
+++ b/content/media/plugins/MediaPluginReader.cpp
@@ -17,6 +17,8 @@
 
 namespace mozilla {
 
+using namespace mozilla::gfx;
+
 typedef mozilla::layers::Image Image;
 typedef mozilla::layers::PlanarYCbCrImage PlanarYCbCrImage;
 
@@ -393,8 +395,8 @@ MediaPluginReader::ImageBufferCallback::CreateI420Image(size_t aWidth,
   frameDesc.mCbChannel = buffer + frameSize;
   frameDesc.mCrChannel = buffer + frameSize * 5 / 4;
 
-  frameDesc.mYSize = gfxIntSize(aWidth, aHeight);
-  frameDesc.mCbCrSize = gfxIntSize(aWidth / 2, aHeight / 2);
+  frameDesc.mYSize = IntSize(aWidth, aHeight);
+  frameDesc.mCbCrSize = IntSize(aWidth / 2, aHeight / 2);
 
   frameDesc.mYStride = aWidth;
   frameDesc.mCbCrStride = aWidth / 2;
@@ -405,7 +407,7 @@ MediaPluginReader::ImageBufferCallback::CreateI420Image(size_t aWidth,
 
   frameDesc.mPicX = 0;
   frameDesc.mPicY = 0;
-  frameDesc.mPicSize = gfxIntSize(aWidth, aHeight);
+  frameDesc.mPicSize = IntSize(aWidth, aHeight);
 
   yuvImage->SetDataNoCopy(frameDesc);
 
diff --git a/content/media/webrtc/MediaEngineDefault.cpp b/content/media/webrtc/MediaEngineDefault.cpp
index 7d78456a02cf..d2fd578d72c1 100644
--- a/content/media/webrtc/MediaEngineDefault.cpp
+++ b/content/media/webrtc/MediaEngineDefault.cpp
@@ -25,6 +25,8 @@
 #define AUDIO_FRAME_LENGTH ((AUDIO_RATE * MediaEngine::DEFAULT_AUDIO_TIMER_MS) / 1000)
 namespace mozilla {
 
+using namespace mozilla::gfx;
+
 NS_IMPL_ISUPPORTS1(MediaEngineDefaultVideoSource, nsITimerCallback)
 /**
  * Default video source.
@@ -92,15 +94,15 @@ static void AllocateSolidColorFrame(layers::PlanarYCbCrData& aData,
   memset(frame+yLen+cbLen, aCr, crLen);
 
   aData.mYChannel = frame;
-  aData.mYSize = gfxIntSize(aWidth, aHeight);
+  aData.mYSize = IntSize(aWidth, aHeight);
   aData.mYStride = aWidth;
   aData.mCbCrStride = aWidth>>1;
   aData.mCbChannel = frame + yLen;
   aData.mCrChannel = aData.mCbChannel + cbLen;
-  aData.mCbCrSize = gfxIntSize(aWidth>>1, aHeight>>1);
+  aData.mCbCrSize = IntSize(aWidth>>1, aHeight>>1);
   aData.mPicX = 0;
   aData.mPicY = 0;
-  aData.mPicSize = gfxIntSize(aWidth, aHeight);
+  aData.mPicSize = IntSize(aWidth, aHeight);
   aData.mStereoMode = STEREO_MODE_MONO;
 }
 
diff --git a/content/media/webrtc/MediaEngineTabVideoSource.cpp b/content/media/webrtc/MediaEngineTabVideoSource.cpp
index e29216d41251..0ce8f36bf3ab 100644
--- a/content/media/webrtc/MediaEngineTabVideoSource.cpp
+++ b/content/media/webrtc/MediaEngineTabVideoSource.cpp
@@ -18,6 +18,8 @@
 #include "nsIPrefService.h"
 namespace mozilla {
 
+using namespace mozilla::gfx;
+
 NS_IMPL_ISUPPORTS1(MediaEngineTabVideoSource, MediaEngineVideoSource)
 
 MediaEngineTabVideoSource::MediaEngineTabVideoSource()
@@ -171,7 +173,7 @@ NotifyPull(MediaStreamGraph*, SourceMediaStream* aSource, mozilla::TrackID aID,
 void
 MediaEngineTabVideoSource::Draw() {
 
-  nsIntSize size(mBufW, mBufH);
+  IntSize size(mBufW, mBufH);
 
   nsresult rv;
   float scale = 1.0;
@@ -241,8 +243,8 @@ MediaEngineTabVideoSource::Draw() {
 
   nsRefPtr<layers::ImageContainer> container = layers::LayerManager::CreateImageContainer();
   nsRefPtr<gfxASurface> surf;
-  surf = new gfxImageSurface(static_cast<unsigned char*>(mData), size,
-                             stride, format);
+  surf = new gfxImageSurface(static_cast<unsigned char*>(mData),
+                             ThebesIntSize(size), stride, format);
   if (surf->CairoStatus() != 0) {
     return;
   }
diff --git a/content/media/webrtc/MediaEngineWebRTCVideo.cpp b/content/media/webrtc/MediaEngineWebRTCVideo.cpp
index 2a34df7a2751..de768b5d19dc 100644
--- a/content/media/webrtc/MediaEngineWebRTCVideo.cpp
+++ b/content/media/webrtc/MediaEngineWebRTCVideo.cpp
@@ -11,6 +11,8 @@
 
 namespace mozilla {
 
+using namespace mozilla::gfx;
+
 #ifdef PR_LOGGING
 extern PRLogModuleInfo* GetMediaManagerLog();
 #define LOG(msg) PR_LOG(GetMediaManagerLog(), PR_LOG_DEBUG, msg)
@@ -77,15 +79,15 @@ MediaEngineWebRTCVideoSource::DeliverFrame(
 
   layers::PlanarYCbCrData data;
   data.mYChannel = frame;
-  data.mYSize = gfxIntSize(mWidth, mHeight);
+  data.mYSize = IntSize(mWidth, mHeight);
   data.mYStride = mWidth * lumaBpp/ 8;
   data.mCbCrStride = mWidth * chromaBpp / 8;
   data.mCbChannel = frame + mHeight * data.mYStride;
   data.mCrChannel = data.mCbChannel + mHeight * data.mCbCrStride / 2;
-  data.mCbCrSize = gfxIntSize(mWidth/ 2, mHeight/ 2);
+  data.mCbCrSize = IntSize(mWidth/ 2, mHeight/ 2);
   data.mPicX = 0;
   data.mPicY = 0;
-  data.mPicSize = gfxIntSize(mWidth, mHeight);
+  data.mPicSize = IntSize(mWidth, mHeight);
   data.mStereoMode = STEREO_MODE_MONO;
 
   videoImage->SetData(data);
diff --git a/dom/camera/GonkCameraControl.cpp b/dom/camera/GonkCameraControl.cpp
index 71cec72fb536..8e68d50cae8e 100644
--- a/dom/camera/GonkCameraControl.cpp
+++ b/dom/camera/GonkCameraControl.cpp
@@ -46,6 +46,7 @@
 using namespace mozilla;
 using namespace mozilla::dom;
 using namespace mozilla::layers;
+using namespace mozilla::gfx;
 using namespace android;
 
 /**
@@ -1693,7 +1694,7 @@ GonkFrameBuilder(Image* aImage, void* aBuffer, uint32_t aWidth, uint32_t aHeight
   GrallocImage* videoImage = static_cast<GrallocImage*>(aImage);
   GrallocImage::GrallocData data;
   data.mGraphicBuffer = static_cast<layers::GraphicBufferLocked*>(aBuffer);
-  data.mPicSize = gfxIntSize(aWidth, aHeight);
+  data.mPicSize = IntSize(aWidth, aHeight);
   videoImage->SetData(data);
 }
 
diff --git a/dom/plugins/base/nsPluginInstanceOwner.cpp b/dom/plugins/base/nsPluginInstanceOwner.cpp
index cb5974fe7358..ef78fcf17a60 100644
--- a/dom/plugins/base/nsPluginInstanceOwner.cpp
+++ b/dom/plugins/base/nsPluginInstanceOwner.cpp
@@ -180,7 +180,7 @@ nsPluginInstanceOwner::GetImageContainer()
   data.mInverted = mInstance->Inverted();
 
   LayoutDeviceRect r = GetPluginRect();
-  data.mSize = gfxIntSize(r.width, r.height);
+  data.mSize = gfx::IntSize(r.width, r.height);
 
   SharedTextureImage* pluginImage = static_cast<SharedTextureImage*>(img.get());
   pluginImage->SetData(data);
@@ -1512,7 +1512,7 @@ already_AddRefed<ImageContainer> nsPluginInstanceOwner::GetImageContainerForVide
   // The logic below for Honeycomb is just a guess, but seems to work. We don't have a separate
   // inverted flag for video.
   data.mInverted = AndroidBridge::Bridge()->IsHoneycomb() ? true : mInstance->Inverted();
-  data.mSize = gfxIntSize(aVideoInfo->mDimensions.width, aVideoInfo->mDimensions.height);
+  data.mSize = gfx::IntSize(aVideoInfo->mDimensions.width, aVideoInfo->mDimensions.height);
 
   SharedTextureImage* pluginImage = static_cast<SharedTextureImage*>(img.get());
   pluginImage->SetData(data);
diff --git a/dom/plugins/ipc/PluginInstanceChild.cpp b/dom/plugins/ipc/PluginInstanceChild.cpp
index b51266985496..36036167cf7a 100644
--- a/dom/plugins/ipc/PluginInstanceChild.cpp
+++ b/dom/plugins/ipc/PluginInstanceChild.cpp
@@ -36,6 +36,7 @@ using namespace mozilla;
 using mozilla::ipc::ProcessChild;
 using namespace mozilla::plugins;
 using namespace mozilla::layers;
+using namespace mozilla::gfx;
 using namespace std;
 
 #ifdef MOZ_WIDGET_GTK
@@ -2578,7 +2579,7 @@ PluginInstanceChild::NPN_FinalizeAsyncSurface(NPAsyncSurface *surface)
                 RemoteImageData *data = mRemoteImageData;
                 if (data->mBitmap.mData == bitmapData->mRemotePtr) {
                     data->mBitmap.mData = nullptr;
-                    data->mSize = gfxIntSize(0, 0);
+                    data->mSize = IntSize(0, 0);
                     data->mWasUpdated = true;
                 }
             }
@@ -2593,7 +2594,7 @@ PluginInstanceChild::NPN_FinalizeAsyncSurface(NPAsyncSurface *surface)
                 RemoteImageData *data = mRemoteImageData;
                 if (data->mTextureHandle == surface->sharedHandle) {
                     data->mTextureHandle = nullptr;
-                    data->mSize = gfxIntSize(0, 0);
+                    data->mSize = IntSize(0, 0);
                     data->mWasUpdated = true;
                 }
             }
@@ -2619,7 +2620,7 @@ PluginInstanceChild::NPN_SetCurrentAsyncSurface(NPAsyncSurface *surface, NPRect
     if (!surface) {
         CrossProcessMutexAutoLock autoLock(*mRemoteImageDataMutex);
         data->mBitmap.mData = nullptr;
-        data->mSize = gfxIntSize(0, 0);
+        data->mSize = IntSize(0, 0);
         data->mWasUpdated = true;
     } else {
         switch (mDrawingModel) {
@@ -2633,7 +2634,7 @@ PluginInstanceChild::NPN_SetCurrentAsyncSurface(NPAsyncSurface *surface, NPRect
               
                 CrossProcessMutexAutoLock autoLock(*mRemoteImageDataMutex);
                 data->mBitmap.mData = (unsigned char*)bitmapData->mRemotePtr;
-                data->mSize = gfxIntSize(surface->size.width, surface->size.height);
+                data->mSize = IntSize(surface->size.width, surface->size.height);
                 data->mFormat = surface->format == NPImageFormatBGRX32 ?
                                 RemoteImageData::BGRX32 : RemoteImageData::BGRA32;
                 data->mBitmap.mStride = surface->bitmap.stride;
@@ -2645,7 +2646,7 @@ PluginInstanceChild::NPN_SetCurrentAsyncSurface(NPAsyncSurface *surface, NPRect
             {
                 CrossProcessMutexAutoLock autoLock(*mRemoteImageDataMutex);
                 data->mType = RemoteImageData::DXGI_TEXTURE_HANDLE;
-                data->mSize = gfxIntSize(surface->size.width, surface->size.height);
+                data->mSize = IntSize(surface->size.width, surface->size.height);
                 data->mFormat = surface->format == NPImageFormatBGRX32 ?
                                 RemoteImageData::BGRX32 : RemoteImageData::BGRA32;
                 data->mTextureHandle = surface->sharedHandle;
diff --git a/dom/plugins/ipc/PluginInstanceParent.cpp b/dom/plugins/ipc/PluginInstanceParent.cpp
index 5e49cb9dcc35..c2651e10aaf9 100644
--- a/dom/plugins/ipc/PluginInstanceParent.cpp
+++ b/dom/plugins/ipc/PluginInstanceParent.cpp
@@ -644,7 +644,7 @@ PluginInstanceParent::RecvShow(const NPRect& updatedRect,
         CairoImage* cairoImage = static_cast<CairoImage*>(image.get());
         CairoImage::Data cairoData;
         cairoData.mSurface = surface;
-        cairoData.mSize = surface->GetSize();
+        cairoData.mSize = surface->GetSize().ToIntSize();
         cairoImage->SetData(cairoData);
 
         container->SetCurrentImage(cairoImage);
diff --git a/gfx/gl/GLTextureImage.cpp b/gfx/gl/GLTextureImage.cpp
index 1fba713c5dec..7f0f8f6b1673 100644
--- a/gfx/gl/GLTextureImage.cpp
+++ b/gfx/gl/GLTextureImage.cpp
@@ -59,15 +59,15 @@ TileGenFunc(GLContext* gl,
             return nullptr;
     }
 }
-already_AddRefed<TextureImage>
 
+already_AddRefed<TextureImage>
 TextureImage::Create(GLContext* gl,
                      const nsIntSize& size,
                      TextureImage::ContentType contentType,
                      GLenum wrapMode,
                      TextureImage::Flags flags)
 {
-    return CreateTextureImage(gl, size, contentType, wrapMode, flags);
+    return Create(gl, size.ToIntSize(), contentType, wrapMode, flags);
 }
 
 // Moz2D equivalent...
@@ -78,7 +78,7 @@ TextureImage::Create(GLContext* gl,
                      GLenum wrapMode,
                      TextureImage::Flags flags)
 {
-    return Create(gl, ThebesIntSize(size), contentType, wrapMode, flags);
+    return CreateTextureImage(gl, size, contentType, wrapMode, flags);
 }
 
 bool
@@ -275,7 +275,7 @@ gfx::IntSize TextureImage::GetSize() const {
 TextureImage::TextureImage(const gfx::IntSize& aSize,
              GLenum aWrapMode, ContentType aContentType,
              Flags aFlags)
-    : mSize(ThebesIntSize(aSize))
+    : mSize(aSize)
     , mWrapMode(aWrapMode)
     , mContentType(aContentType)
     , mFilter(GraphicsFilter::FILTER_GOOD)
diff --git a/gfx/gl/GLTextureImage.h b/gfx/gl/GLTextureImage.h
index 6f434b6f262e..c4ed590f2f00 100644
--- a/gfx/gl/GLTextureImage.h
+++ b/gfx/gl/GLTextureImage.h
@@ -223,7 +223,7 @@ protected:
                  GLenum aWrapMode, ContentType aContentType,
                  Flags aFlags = NoFlags,
                  ImageFormat aImageFormat = gfxImageFormatUnknown)
-        : mSize(aSize)
+        : mSize(aSize.ToIntSize())
         , mWrapMode(aWrapMode)
         , mContentType(aContentType)
         , mImageFormat(aImageFormat)
diff --git a/gfx/gl/SharedSurfaceGralloc.cpp b/gfx/gl/SharedSurfaceGralloc.cpp
index d34044a1ad61..d27c4557e8f9 100644
--- a/gfx/gl/SharedSurfaceGralloc.cpp
+++ b/gfx/gl/SharedSurfaceGralloc.cpp
@@ -75,7 +75,7 @@ SharedSurface_Gralloc::Create(GLContext* prodGL,
 
     gfxContentType type = hasAlpha ? GFX_CONTENT_COLOR_ALPHA
                                                 : GFX_CONTENT_COLOR;
-    if (!allocator->AllocSurfaceDescriptorWithCaps(size, type, USING_GL_RENDERING_ONLY, &baseDesc))
+    if (!allocator->AllocSurfaceDescriptorWithCaps(size.ToIntSize(), type, USING_GL_RENDERING_ONLY, &baseDesc))
         return false;
 
     if (baseDesc.type() != SurfaceDescriptor::TSurfaceDescriptorGralloc) {
diff --git a/gfx/layers/ImageContainer.cpp b/gfx/layers/ImageContainer.cpp
index a4747fb198c8..d6c8b8e0a002 100644
--- a/gfx/layers/ImageContainer.cpp
+++ b/gfx/layers/ImageContainer.cpp
@@ -317,7 +317,7 @@ ImageContainer::LockCurrentAsSurface(gfx::IntSize *aSize, Image** aCurrentImage)
                                                    gfxImageFormatARGB32 :
                                                    gfxImageFormatRGB24);
 
-      *aSize = newSurf->GetSize();
+      *aSize = newSurf->GetSize().ToIntSize();
     
       return newSurf.forget();
     }
@@ -382,7 +382,7 @@ ImageContainer::GetCurrentSize()
   }
 
   if (!mActiveImage) {
-    return gfx::IntSize(0,0);
+    return gfx::IntSize(0, 0);
   }
 
   return mActiveImage->GetSize();
diff --git a/gfx/layers/client/ClientLayerManager.cpp b/gfx/layers/client/ClientLayerManager.cpp
index 72cd6a654ac6..f853fc6a5475 100644
--- a/gfx/layers/client/ClientLayerManager.cpp
+++ b/gfx/layers/client/ClientLayerManager.cpp
@@ -273,7 +273,7 @@ ClientLayerManager::MakeSnapshotIfRequired()
       nsIntRect bounds;
       mWidget->GetBounds(bounds);
       SurfaceDescriptor inSnapshot, snapshot;
-      if (mForwarder->AllocSurfaceDescriptor(bounds.Size(),
+      if (mForwarder->AllocSurfaceDescriptor(bounds.Size().ToIntSize(),
                                              GFX_CONTENT_COLOR_ALPHA,
                                              &inSnapshot) &&
           // The compositor will usually reuse |snapshot| and return
diff --git a/gfx/layers/client/ContentClient.cpp b/gfx/layers/client/ContentClient.cpp
index 544784812d91..ea7e54715d05 100644
--- a/gfx/layers/client/ContentClient.cpp
+++ b/gfx/layers/client/ContentClient.cpp
@@ -1147,8 +1147,8 @@ ContentClientIncremental::BeginPaintBuffer(ThebesLayer* aLayer,
       FillSurface(onBlack, result.mRegionToDraw, nsIntPoint(drawBounds.x, drawBounds.y), gfxRGBA(0.0, 0.0, 0.0, 1.0));
       FillSurface(onWhite, result.mRegionToDraw, nsIntPoint(drawBounds.x, drawBounds.y), gfxRGBA(1.0, 1.0, 1.0, 1.0));
       MOZ_ASSERT(gfxPlatform::GetPlatform()->SupportsAzureContent());
-      RefPtr<DrawTarget> onBlackDT = gfxPlatform::GetPlatform()->CreateDrawTargetForUpdateSurface(onBlack, onBlack->GetSize());
-      RefPtr<DrawTarget> onWhiteDT = gfxPlatform::GetPlatform()->CreateDrawTargetForUpdateSurface(onWhite, onWhite->GetSize());
+      RefPtr<DrawTarget> onBlackDT = gfxPlatform::GetPlatform()->CreateDrawTargetForUpdateSurface(onBlack, onBlack->GetSize().ToIntSize());
+      RefPtr<DrawTarget> onWhiteDT = gfxPlatform::GetPlatform()->CreateDrawTargetForUpdateSurface(onWhite, onWhite->GetSize().ToIntSize());
       RefPtr<DrawTarget> dt = Factory::CreateDualDrawTarget(onBlackDT, onWhiteDT);
       result.mContext = new gfxContext(dt);
     } else {
@@ -1157,7 +1157,7 @@ ContentClientIncremental::BeginPaintBuffer(ThebesLayer* aLayer,
   } else {
     nsRefPtr<gfxASurface> surf = GetUpdateSurface(BUFFER_BLACK, result.mRegionToDraw);
     MOZ_ASSERT(gfxPlatform::GetPlatform()->SupportsAzureContent());
-    RefPtr<DrawTarget> dt = gfxPlatform::GetPlatform()->CreateDrawTargetForUpdateSurface(surf, surf->GetSize());
+    RefPtr<DrawTarget> dt = gfxPlatform::GetPlatform()->CreateDrawTargetForUpdateSurface(surf, surf->GetSize().ToIntSize());
     result.mContext = new gfxContext(dt);
   }
   if (!result.mContext) {
@@ -1226,7 +1226,7 @@ ContentClientIncremental::GetUpdateSurface(BufferType aType,
     return nullptr;
   }
   SurfaceDescriptor desc;
-  if (!mForwarder->AllocSurfaceDescriptor(gfxIntSize(rgnSize.width, rgnSize.height),
+  if (!mForwarder->AllocSurfaceDescriptor(rgnSize.Size().ToIntSize(),
                                           mContentType,
                                           &desc)) {
     NS_WARNING("creating SurfaceDescriptor failed!");
diff --git a/gfx/layers/client/TextureClient.cpp b/gfx/layers/client/TextureClient.cpp
index 696b3ec86735..9c5a598b0bc7 100644
--- a/gfx/layers/client/TextureClient.cpp
+++ b/gfx/layers/client/TextureClient.cpp
@@ -533,8 +533,8 @@ BufferTextureClient::UpdateYCbCr(const PlanarYCbCrData& aData)
   YCbCrImageDataSerializer serializer(GetBuffer());
   MOZ_ASSERT(serializer.IsValid());
   if (!serializer.CopyData(aData.mYChannel, aData.mCbChannel, aData.mCrChannel,
-                           ThebesIntSize(aData.mYSize), aData.mYStride,
-                           ThebesIntSize(aData.mCbCrSize), aData.mCbCrStride,
+                           aData.mYSize, aData.mYStride,
+                           aData.mCbCrSize, aData.mCbCrStride,
                            aData.mYSkip, aData.mCbSkip)) {
     NS_WARNING("Failed to copy image data!");
     return false;
@@ -635,8 +635,8 @@ DeprecatedTextureClientShmem::EnsureAllocated(gfx::IntSize aSize,
     mContentType = aContentType;
     mSize = aSize;
 
-    if (!mForwarder->AllocSurfaceDescriptor(gfxIntSize(mSize.width, mSize.height),
-                                            mContentType, &mDescriptor)) {
+    if (!mForwarder->AllocSurfaceDescriptor(mSize, mContentType,
+                                            &mDescriptor)) {
       NS_WARNING("creating SurfaceDescriptor failed!");
     }
     if (mContentType == GFX_CONTENT_COLOR_ALPHA) {
@@ -885,8 +885,8 @@ AutoLockYCbCrClient::Update(PlanarYCbCrImage* aImage)
 
   YCbCrImageDataSerializer serializer(shmem.get<uint8_t>());
   if (!serializer.CopyData(data->mYChannel, data->mCbChannel, data->mCrChannel,
-                           ThebesIntSize(data->mYSize), data->mYStride,
-                           ThebesIntSize(data->mCbCrSize), data->mCbCrStride,
+                           data->mYSize, data->mYStride,
+                           data->mCbCrSize, data->mCbCrStride,
                            data->mYSkip, data->mCbSkip)) {
     NS_WARNING("Failed to copy image data!");
     return false;
diff --git a/gfx/layers/composite/ContentHost.cpp b/gfx/layers/composite/ContentHost.cpp
index 39f057ecffa7..403694de2963 100644
--- a/gfx/layers/composite/ContentHost.cpp
+++ b/gfx/layers/composite/ContentHost.cpp
@@ -523,7 +523,7 @@ ContentHostSingleBuffered::UpdateThebes(const ThebesBufferData& aData,
   // Correct for rotation
   destRegion.MoveBy(aData.rotation());
 
-  IntSize size = aData.rect().Size();
+  IntSize size = aData.rect().Size().ToIntSize();
   nsIntRect destBounds = destRegion.GetBounds();
   destRegion.MoveBy((destBounds.x >= size.width) ? -size.width : 0,
                     (destBounds.y >= size.height) ? -size.height : 0);
@@ -620,7 +620,7 @@ DeprecatedContentHostSingleBuffered::UpdateThebes(const ThebesBufferData& aData,
   // Correct for rotation
   destRegion.MoveBy(aData.rotation());
 
-  IntSize size = aData.rect().Size();
+  IntSize size = aData.rect().Size().ToIntSize();
   nsIntRect destBounds = destRegion.GetBounds();
   destRegion.MoveBy((destBounds.x >= size.width) ? -size.width : 0,
                     (destBounds.y >= size.height) ? -size.height : 0);
diff --git a/gfx/layers/d3d10/ImageLayerD3D10.cpp b/gfx/layers/d3d10/ImageLayerD3D10.cpp
index 4d12543c59a0..f16a430547be 100644
--- a/gfx/layers/d3d10/ImageLayerD3D10.cpp
+++ b/gfx/layers/d3d10/ImageLayerD3D10.cpp
@@ -414,7 +414,7 @@ ImageLayerD3D10::GetAsTexture(gfx::IntSize* aSize)
     return nullptr;
   }
 
-  *aSize = gfx::ThebesIntSize(image->GetSize());
+  *aSize = image->GetSize();
   bool dontCare;
   nsRefPtr<ID3D10ShaderResourceView> result = GetImageSRView(image, dontCare);
   return result.forget();
diff --git a/gfx/layers/d3d11/CompositorD3D11.cpp b/gfx/layers/d3d11/CompositorD3D11.cpp
index 054316163b1c..ed21705f3fed 100644
--- a/gfx/layers/d3d11/CompositorD3D11.cpp
+++ b/gfx/layers/d3d11/CompositorD3D11.cpp
@@ -788,7 +788,7 @@ CompositorD3D11::UpdateRenderTarget()
   }
 
   mDefaultRT = new CompositingRenderTargetD3D11(backBuf, IntPoint(0, 0));
-  mDefaultRT->SetSize(mSize);
+  mDefaultRT->SetSize(mSize.ToIntSize());
 }
 
 bool
diff --git a/gfx/layers/d3d9/ImageLayerD3D9.cpp b/gfx/layers/d3d9/ImageLayerD3D9.cpp
index b336548972d1..909dc92e1f46 100644
--- a/gfx/layers/d3d9/ImageLayerD3D9.cpp
+++ b/gfx/layers/d3d9/ImageLayerD3D9.cpp
@@ -568,7 +568,7 @@ ImageLayerD3D9::GetAsTexture(gfx::IntSize* aSize)
   }
 
   bool dontCare;
-  *aSize = gfx::ThebesIntSize(image->GetSize());
+  *aSize = image->GetSize();
   nsRefPtr<IDirect3DTexture9> result = GetTexture(image, dontCare);
   return result.forget();
 }
diff --git a/gfx/layers/ipc/ShadowLayerUtilsX11.cpp b/gfx/layers/ipc/ShadowLayerUtilsX11.cpp
index 23559401c63f..711e8d1b53a7 100644
--- a/gfx/layers/ipc/ShadowLayerUtilsX11.cpp
+++ b/gfx/layers/ipc/ShadowLayerUtilsX11.cpp
@@ -76,7 +76,7 @@ TakeAndDestroyXlibSurface(SurfaceDescriptor* aSurface)
 
 SurfaceDescriptorX11::SurfaceDescriptorX11(gfxXlibSurface* aSurf)
   : mId(aSurf->XDrawable())
-  , mSize(aSurf->GetSize())
+  , mSize(aSurf->GetSize().ToIntSize())
 {
   const XRenderPictFormat *pictFormat = aSurf->XRenderFormat();
   if (pictFormat) {
diff --git a/gfx/layers/ipc/ShadowLayers.cpp b/gfx/layers/ipc/ShadowLayers.cpp
index 25d268bddac6..6c0d155e14b6 100644
--- a/gfx/layers/ipc/ShadowLayers.cpp
+++ b/gfx/layers/ipc/ShadowLayers.cpp
@@ -669,8 +669,8 @@ ShadowLayerForwarder::GetDescriptorSurfaceSize(
   }
 
   nsRefPtr<gfxASurface> surface = OpenDescriptor(aMode, aDescriptor);
-  size = surface->GetSize();
-  *aSurface = surface.forget().get();
+  size = surface->GetSize().ToIntSize();
+  surface.forget(aSurface);
   return size;
 }
 
@@ -829,7 +829,7 @@ gfx::IntSize
 AutoOpenSurface::Size()
 {
   if (mSurface) {
-    return mSurface->GetSize();
+    return mSurface->GetSize().ToIntSize();
   }
   return ShadowLayerForwarder::GetDescriptorSurfaceSize(
     mDescriptor, mMode, getter_AddRefs(mSurface));
diff --git a/gfx/layers/ipc/SharedPlanarYCbCrImage.cpp b/gfx/layers/ipc/SharedPlanarYCbCrImage.cpp
index 35a371d345c8..187947d87278 100644
--- a/gfx/layers/ipc/SharedPlanarYCbCrImage.cpp
+++ b/gfx/layers/ipc/SharedPlanarYCbCrImage.cpp
@@ -246,9 +246,9 @@ DeprecatedSharedPlanarYCbCrImage::SetData(const PlanarYCbCrData& aData)
   YCbCrImageDataSerializer serializer(mShmem.get<uint8_t>());
   MOZ_ASSERT(aData.mCbSkip == aData.mCrSkip);
   if (!serializer.CopyData(aData.mYChannel, aData.mCbChannel, aData.mCrChannel,
-                          ThebesIntSize(aData.mYSize), aData.mYStride,
-                          ThebesIntSize(aData.mCbCrSize), aData.mCbCrStride,
-                          aData.mYSkip, aData.mCbSkip)) {
+                           aData.mYSize, aData.mYStride,
+                           aData.mCbCrSize, aData.mCbCrStride,
+                           aData.mYSkip, aData.mCbSkip)) {
     NS_WARNING("Failed to copy image data!");
   }
   mData.mYChannel = serializer.GetYData();
diff --git a/gfx/layers/ipc/SharedRGBImage.cpp b/gfx/layers/ipc/SharedRGBImage.cpp
index 849cbdf72ce5..9eadd91901c8 100644
--- a/gfx/layers/ipc/SharedRGBImage.cpp
+++ b/gfx/layers/ipc/SharedRGBImage.cpp
@@ -74,7 +74,7 @@ CreateSharedRGBImage(ImageContainer *aImageContainer,
 
   if (gfxPlatform::GetPlatform()->UseDeprecatedTextures()) {
     nsRefPtr<DeprecatedSharedRGBImage> rgbImageDep = static_cast<DeprecatedSharedRGBImage*>(image.get());
-    rgbImageDep->mSize = gfxIntSize(aSize.width, aSize.height);
+    rgbImageDep->mSize = aSize.ToIntSize();
     rgbImageDep->mImageFormat = aImageFormat;
 
     if (!rgbImageDep->AllocateBuffer(aSize, aImageFormat)) {
@@ -218,7 +218,7 @@ SharedRGBImage::GetBuffer()
 gfx::IntSize
 SharedRGBImage::GetSize()
 {
-  return ThebesIntSize(mSize);
+  return mSize;
 }
 
 size_t
diff --git a/gfx/layers/opengl/GrallocTextureClient.cpp b/gfx/layers/opengl/GrallocTextureClient.cpp
index 01805ca69f27..37d2f01c4df3 100644
--- a/gfx/layers/opengl/GrallocTextureClient.cpp
+++ b/gfx/layers/opengl/GrallocTextureClient.cpp
@@ -16,6 +16,7 @@
 namespace mozilla {
 namespace layers {
 
+using namespace mozilla::gfx;
 using namespace android;
 
 class GraphicBufferLockedTextureClientData : public TextureClientData {
@@ -61,7 +62,8 @@ public:
     // We just need to wrap the actor in a SurfaceDescriptor because that's what
     // ISurfaceAllocator uses as input, we don't care about the other parameters.
     SurfaceDescriptor sd = SurfaceDescriptorGralloc(nullptr, mGrallocActor,
-                                                    nsIntSize(0,0), false, false);
+                                                    IntSize(0, 0),
+                                                    false, false);
     allocator->DestroySharedSurface(&sd);
     mGrallocActor = nullptr;
   }
@@ -121,7 +123,8 @@ GrallocTextureClientOGL::~GrallocTextureClientOGL()
       // We just need to wrap the actor in a SurfaceDescriptor because that's what
       // ISurfaceAllocator uses as input, we don't care about the other parameters.
       SurfaceDescriptor sd = SurfaceDescriptorGralloc(nullptr, mGrallocActor,
-                                                      nsIntSize(0,0), false, false);
+                                                      IntSize(0, 0),
+                                                      false, false);
       mCompositable->GetForwarder()->DestroySharedSurface(&sd);
     }
   }
diff --git a/gfx/layers/opengl/TextureClientOGL.cpp b/gfx/layers/opengl/TextureClientOGL.cpp
index e52858850ccc..4f009059cad2 100644
--- a/gfx/layers/opengl/TextureClientOGL.cpp
+++ b/gfx/layers/opengl/TextureClientOGL.cpp
@@ -38,8 +38,7 @@ SharedTextureClientOGL::ToSurfaceDescriptor(SurfaceDescriptor& aOutDescriptor)
   if (!IsAllocated()) {
     return false;
   }
-  nsIntSize nsSize(mSize.width, mSize.height);
-  aOutDescriptor = SharedTextureDescriptor(mShareType, mHandle, nsSize, mInverted);
+  aOutDescriptor = SharedTextureDescriptor(mShareType, mHandle, mSize, mInverted);
   return true;
 }
 
diff --git a/gfx/layers/opengl/TextureHostOGL.cpp b/gfx/layers/opengl/TextureHostOGL.cpp
index 719bc74a9919..a9ddfc31d1cc 100644
--- a/gfx/layers/opengl/TextureHostOGL.cpp
+++ b/gfx/layers/opengl/TextureHostOGL.cpp
@@ -236,7 +236,7 @@ TextureImageTextureSourceOGL::Update(gfx::DataSourceSurface* aSurface,
   }
   MOZ_ASSERT(aSurface);
 
-  nsIntSize size = ThebesIntSize(aSurface->GetSize());
+  IntSize size = aSurface->GetSize();
   if (!mTexImage ||
       mTexImage->GetSize() != size ||
       mTexImage->GetContentType() != gfx::ContentForFormat(aSurface->GetFormat())) {
@@ -501,15 +501,15 @@ TextureImageDeprecatedTextureHostOGL::EnsureBuffer(const nsIntSize& aSize,
                                          gfxContentType aContentType)
 {
   if (!mTexture ||
-      mTexture->GetSize() != aSize ||
+      mTexture->GetSize() != aSize.ToIntSize() ||
       mTexture->GetContentType() != aContentType) {
     mTexture = CreateTextureImage(mGL,
-                                  aSize,
+                                  aSize.ToIntSize(),
                                   aContentType,
                                   WrapMode(mGL, mFlags & TEXTURE_ALLOW_REPEAT),
                                   FlagsToGLFlags(mFlags));
   }
-  mTexture->Resize(aSize);
+  mTexture->Resize(aSize.ToIntSize());
 }
 
 void
diff --git a/gfx/src/nsSize.h b/gfx/src/nsSize.h
index cc0d7975003e..f56cc735b621 100644
--- a/gfx/src/nsSize.h
+++ b/gfx/src/nsSize.h
@@ -37,7 +37,10 @@ struct nsIntSize : public mozilla::gfx::BaseSize<int32_t, nsIntSize> {
   nsIntSize(int32_t aWidth, int32_t aHeight) : Super(aWidth, aHeight) {}
 
   inline nsSize ToAppUnits(nscoord aAppUnitsPerPixel) const;
-  operator mozilla::gfx::IntSize() const { return mozilla::gfx::IntSize(width, height); };
+  mozilla::gfx::IntSize ToIntSize() const
+  {
+    return mozilla::gfx::IntSize(width, height);
+  };
 };
 
 inline nsIntSize
diff --git a/gfx/tests/gtest/TestTextures.cpp b/gfx/tests/gtest/TestTextures.cpp
index 2392111c8b4f..b35dc81f60fd 100644
--- a/gfx/tests/gtest/TestTextures.cpp
+++ b/gfx/tests/gtest/TestTextures.cpp
@@ -242,9 +242,9 @@ TEST(Layers, TextureYCbCrSerialization) {
   clientData.mYChannel = ySurface->Data();
   clientData.mCbChannel = cbSurface->Data();
   clientData.mCrChannel = crSurface->Data();
-  clientData.mYSize = ySurface->GetSize();
-  clientData.mPicSize = ySurface->GetSize();
-  clientData.mCbCrSize = cbSurface->GetSize();
+  clientData.mYSize = ySurface->GetSize().ToIntSize();
+  clientData.mPicSize = ySurface->GetSize().ToIntSize();
+  clientData.mCbCrSize = cbSurface->GetSize().ToIntSize();
   clientData.mYStride = ySurface->Stride();
   clientData.mCbCrStride = cbSurface->Stride();
   clientData.mStereoMode = STEREO_MODE_MONO;
diff --git a/image/src/VectorImage.cpp b/image/src/VectorImage.cpp
index aaadb9cc9b1c..0273fd62a991 100644
--- a/image/src/VectorImage.cpp
+++ b/image/src/VectorImage.cpp
@@ -851,7 +851,7 @@ VectorImage::CreateDrawableAndShow(const SVGDrawingParameters& aParams)
 
   // Try to create an offscreen surface.
   mozilla::RefPtr<mozilla::gfx::DrawTarget> target =
-   gfxPlatform::GetPlatform()->CreateOffscreenContentDrawTarget(aParams.imageRect.Size(), gfx::FORMAT_B8G8R8A8);
+   gfxPlatform::GetPlatform()->CreateOffscreenContentDrawTarget(aParams.imageRect.Size().ToIntSize(), gfx::FORMAT_B8G8R8A8);
 
   // If we couldn't create the draw target, it was probably because it would end
   // up way too big. Generally it also wouldn't fit in the cache, but the prefs
diff --git a/layout/base/FrameLayerBuilder.cpp b/layout/base/FrameLayerBuilder.cpp
index 16a730f91ad6..285002ef0c5d 100644
--- a/layout/base/FrameLayerBuilder.cpp
+++ b/layout/base/FrameLayerBuilder.cpp
@@ -3788,8 +3788,8 @@ ContainerState::SetupMaskLayer(Layer *aLayer, const DisplayItemClip& aClip,
     GetMaskLayerImageCache()->FindImageFor(&lookupKey);
 
   if (!container) {
-    nsIntSize surfaceSizeInt = nsIntSize(NSToIntCeil(surfaceSize.width),
-                                         NSToIntCeil(surfaceSize.height));
+    IntSize surfaceSizeInt(NSToIntCeil(surfaceSize.width),
+                           NSToIntCeil(surfaceSize.height));
     // no existing mask image, so build a new one
     nsRefPtr<gfxASurface> surface =
       aLayer->Manager()->CreateOptimalMaskSurface(surfaceSizeInt);
diff --git a/layout/generic/nsObjectFrame.cpp b/layout/generic/nsObjectFrame.cpp
index bcdb03e37604..7b91bc9ef77d 100644
--- a/layout/generic/nsObjectFrame.cpp
+++ b/layout/generic/nsObjectFrame.cpp
@@ -8,6 +8,7 @@
 
 #include "nsObjectFrame.h"
 
+#include "gfx2DGlue.h"
 #include "mozilla/BasicEvents.h"
 #ifdef XP_WIN
 // This is needed for DoublePassRenderingEvent.
@@ -145,6 +146,7 @@ extern "C" {
 #endif /* #if defined(XP_MACOSX) && !defined(__LP64__) */
 
 using namespace mozilla;
+using namespace mozilla::gfx;
 using namespace mozilla::layers;
 
 class PluginBackgroundSink : public ReadbackSink {
@@ -1527,7 +1529,7 @@ nsObjectFrame::BuildLayer(nsDisplayListBuilder* aBuilder,
     scaleFactor = 1.0;
   }
   int intScaleFactor = ceil(scaleFactor);
-  gfxIntSize size(window->width * intScaleFactor, window->height * intScaleFactor);
+  IntSize size(window->width * intScaleFactor, window->height * intScaleFactor);
 
   nsRect area = GetContentRectRelativeToSelf() + aItem->ToReferenceFrame();
   gfxRect r = nsLayoutUtils::RectToGfxRect(area, PresContext()->AppUnitsPerDevPixel());
@@ -1612,11 +1614,11 @@ nsObjectFrame::BuildLayer(nsDisplayListBuilder* aBuilder,
     NS_ASSERTION(layer->GetType() == Layer::TYPE_READBACK, "Bad layer type");
 
     ReadbackLayer* readback = static_cast<ReadbackLayer*>(layer.get());
-    if (readback->GetSize() != nsIntSize(size.width, size.height)) {
+    if (readback->GetSize() != ThebesIntSize(size)) {
       // This will destroy any old background sink and notify us that the
       // background is now unknown
       readback->SetSink(nullptr);
-      readback->SetSize(nsIntSize(size.width, size.height));
+      readback->SetSize(ThebesIntSize(size));
 
       if (mBackgroundSink) {
         // Maybe we still have a background sink associated with another
@@ -1639,7 +1641,7 @@ nsObjectFrame::BuildLayer(nsDisplayListBuilder* aBuilder,
   transform.Translate(r.TopLeft() + aContainerParameters.mOffset);
 
   layer->SetBaseTransform(gfx3DMatrix::From2D(transform));
-  layer->SetVisibleRegion(nsIntRect(0, 0, size.width, size.height));
+  layer->SetVisibleRegion(ThebesIntRect(IntRect(IntPoint(0, 0), size)));
   return layer.forget();
 }
 
diff --git a/layout/generic/nsVideoFrame.cpp b/layout/generic/nsVideoFrame.cpp
index 415062bc4d1d..f39859620322 100644
--- a/layout/generic/nsVideoFrame.cpp
+++ b/layout/generic/nsVideoFrame.cpp
@@ -31,6 +31,7 @@
 using namespace mozilla;
 using namespace mozilla::layers;
 using namespace mozilla::dom;
+using namespace mozilla::gfx;
 
 nsIFrame*
 NS_NewHTMLVideoFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
@@ -198,8 +199,8 @@ nsVideoFrame::BuildLayer(nsDisplayListBuilder* aBuilder,
   if (r.IsEmpty()) {
     return nullptr;
   }
-  gfxIntSize scaleHint(static_cast<int32_t>(r.Width()),
-                       static_cast<int32_t>(r.Height()));
+  IntSize scaleHint(static_cast<int32_t>(r.Width()),
+                    static_cast<int32_t>(r.Height()));
   container->SetScaleHint(scaleHint);
 
   nsRefPtr<ImageLayer> layer = static_cast<ImageLayer*>
diff --git a/media/webrtc/signaling/src/mediapipeline/MediaPipeline.cpp b/media/webrtc/signaling/src/mediapipeline/MediaPipeline.cpp
index 2e2b825c6bde..d7240d142e93 100644
--- a/media/webrtc/signaling/src/mediapipeline/MediaPipeline.cpp
+++ b/media/webrtc/signaling/src/mediapipeline/MediaPipeline.cpp
@@ -42,6 +42,7 @@
 #include "mozilla/gfx/Point.h"
 
 using namespace mozilla;
+using namespace mozilla::gfx;
 
 // Logging context
 MOZ_MTLOG_MODULE("mediapipeline")
@@ -1212,15 +1213,15 @@ void MediaPipelineReceiveVideo::PipelineListener::RenderVideoFrame(
 
   layers::PlanarYCbCrData data;
   data.mYChannel = frame;
-  data.mYSize = gfxIntSize(width_, height_);
+  data.mYSize = IntSize(width_, height_);
   data.mYStride = width_ * lumaBpp/ 8;
   data.mCbCrStride = width_ * chromaBpp / 8;
   data.mCbChannel = frame + height_ * data.mYStride;
   data.mCrChannel = data.mCbChannel + height_ * data.mCbCrStride / 2;
-  data.mCbCrSize = gfxIntSize(width_/ 2, height_/ 2);
+  data.mCbCrSize = IntSize(width_/ 2, height_/ 2);
   data.mPicX = 0;
   data.mPicY = 0;
-  data.mPicSize = gfxIntSize(width_, height_);
+  data.mPicSize = IntSize(width_, height_);
   data.mStereoMode = STEREO_MODE_MONO;
 
   videoImage->SetData(data);
diff --git a/media/webrtc/signaling/src/peerconnection/PeerConnectionMedia.h b/media/webrtc/signaling/src/peerconnection/PeerConnectionMedia.h
index 0b95de101f83..fd3721d3a773 100644
--- a/media/webrtc/signaling/src/peerconnection/PeerConnectionMedia.h
+++ b/media/webrtc/signaling/src/peerconnection/PeerConnectionMedia.h
@@ -94,6 +94,7 @@ Fake_AudioGenerator(DOMMediaStream* aStream) : mStream(aStream), mCount(0) {
 class Fake_VideoGenerator {
  public:
   typedef mozilla::DOMMediaStream DOMMediaStream;
+  typedef mozilla::gfx::IntSize IntSize;
 
   Fake_VideoGenerator(DOMMediaStream* aStream) {
     mStream = aStream;
@@ -135,15 +136,15 @@ class Fake_VideoGenerator {
 
     mozilla::layers::PlanarYCbCrData data;
     data.mYChannel = frame;
-    data.mYSize = gfxIntSize(WIDTH, HEIGHT);
+    data.mYSize = IntSize(WIDTH, HEIGHT);
     data.mYStride = (int32_t) (WIDTH * lumaBpp / 8.0);
     data.mCbCrStride = (int32_t) (WIDTH * chromaBpp / 8.0);
     data.mCbChannel = frame + HEIGHT * data.mYStride;
     data.mCrChannel = data.mCbChannel + HEIGHT * data.mCbCrStride / 2;
-    data.mCbCrSize = gfxIntSize(WIDTH / 2, HEIGHT / 2);
+    data.mCbCrSize = IntSize(WIDTH / 2, HEIGHT / 2);
     data.mPicX = 0;
     data.mPicY = 0;
-    data.mPicSize = gfxIntSize(WIDTH, HEIGHT);
+    data.mPicSize = IntSize(WIDTH, HEIGHT);
     data.mStereoMode = mozilla::STEREO_MODE_MONO;
 
     // SetData copies data, so we can free the frame
diff --git a/widget/gonk/nativewindow/GonkBufferQueue.cpp b/widget/gonk/nativewindow/GonkBufferQueue.cpp
index 46aab8f82f7a..865cb66d2afa 100755
--- a/widget/gonk/nativewindow/GonkBufferQueue.cpp
+++ b/widget/gonk/nativewindow/GonkBufferQueue.cpp
@@ -37,6 +37,8 @@
 
 #define ATRACE_BUFFER_INDEX(index)
 
+using namespace mozilla;
+using namespace mozilla::gfx;
 using namespace mozilla::layers;
 
 namespace android {
@@ -410,7 +412,7 @@ status_t GonkBufferQueue::dequeueBuffer(int *outBuf, sp<Fence>* outFence,
         status_t error;
         ibc = ImageBridgeChild::GetSingleton();
         ST_LOGD("dequeueBuffer: about to alloc surface descriptor");
-        ibc->AllocSurfaceDescriptorGralloc(gfxIntSize(w, h),
+        ibc->AllocSurfaceDescriptorGralloc(IntSize(w, h),
                                            format,
                                            usage,
                                            &desc);
diff --git a/widget/gonk/nativewindow/GonkNativeWindowICS.cpp b/widget/gonk/nativewindow/GonkNativeWindowICS.cpp
index 1560d572f681..4bf7b7b4009a 100644
--- a/widget/gonk/nativewindow/GonkNativeWindowICS.cpp
+++ b/widget/gonk/nativewindow/GonkNativeWindowICS.cpp
@@ -32,6 +32,8 @@
 #define CNW_LOGE(...)   {(void)printf_stderr(__VA_ARGS__);}
 
 using namespace android;
+using namespace mozilla;
+using namespace mozilla::gfx;
 using namespace mozilla::layers;
 
 GonkNativeWindow::GonkNativeWindow() :
@@ -338,7 +340,7 @@ status_t GonkNativeWindow::dequeueBuffer(int *outBuf, uint32_t w, uint32_t h,
         status_t error;
         ibc = ImageBridgeChild::GetSingleton();
         CNW_LOGD("dequeueBuffer: about to alloc surface descriptor");
-        ibc->AllocSurfaceDescriptorGralloc(gfxIntSize(w, h),
+        ibc->AllocSurfaceDescriptorGralloc(IntSize(w, h),
                                            format,
                                            usage,
                                            &desc);
diff --git a/widget/gtk/nsWindow.cpp b/widget/gtk/nsWindow.cpp
index d00f34cca8c3..f30fb4767d01 100644
--- a/widget/gtk/nsWindow.cpp
+++ b/widget/gtk/nsWindow.cpp
@@ -2289,8 +2289,7 @@ nsWindow::UpdateAlpha(gfxPattern* aPattern, nsIntRect aBoundsRect)
       UpdateTranslucentWindowAlphaInternal(aBoundsRect, imageBuffer, stride);
   } else {
       nsRefPtr<gfxImageSurface> img =
-          new gfxImageSurface(ThebesIntSize(aBoundsRect.Size()),
-                              gfxImageFormatA8);
+          new gfxImageSurface(aBoundsRect.Size(), gfxImageFormatA8);
       if (img && !img->CairoStatus()) {
           img->SetDeviceOffset(-aBoundsRect.TopLeft());