Bug 1321075: Check if the backend is friendly to data draw target creation before attempting to make it. r=bas

MozReview-Commit-ID: 8jvUvrmCTAY

--HG--
extra : rebase_source : 1325c3cc3a1b02b96bb4b3cb249afeeae7a77864

gfx/layers/BufferTexture.cpp

@@ -282,9 +282,17 @@ BufferTextureData::BorrowDrawTarget()
   const RGBDescriptor& rgb = mDescriptor.get_RGBDescriptor();
 
   uint32_t stride = ImageDataSerializer::GetRGBStride(rgb);
-  mDrawTarget = gfx::Factory::CreateDrawTargetForData(mMoz2DBackend,
-                                                      GetBuffer(), rgb.size(),
-                                                      stride, rgb.format(), true);
+  if (gfx::Factory::DoesBackendSupportDataDrawtarget(mMoz2DBackend)) {
+    mDrawTarget = gfx::Factory::CreateDrawTargetForData(mMoz2DBackend,
+                                                        GetBuffer(), rgb.size(),
+                                                        stride, rgb.format(), true);
+  } else {
+    // Fall back to supported platform backend.  Note that mMoz2DBackend
+    // does not match the draw target type.
+    mDrawTarget = gfxPlatform::CreateDrawTargetForData(GetBuffer(), rgb.size(),
+                                                       stride, rgb.format(),
+                                                       true);
+  }
 
   if (mDrawTarget) {
     RefPtr<gfx::DrawTarget> dt = mDrawTarget;
@@ -294,6 +302,7 @@ BufferTextureData::BorrowDrawTarget()
   // TODO - should we warn? should we really fallback to cairo? perhaps
   // at least update mMoz2DBackend...
   if (mMoz2DBackend != gfx::BackendType::CAIRO) {
+    gfxCriticalNote << "Falling to CAIRO from " << (int)mMoz2DBackend;
     mDrawTarget = gfx::Factory::CreateDrawTargetForData(gfx::BackendType::CAIRO,
                                                         GetBuffer(), rgb.size(),
                                                         stride, rgb.format(), true);

gfx/thebes/gfxPlatform.cpp

@@ -1469,7 +1469,11 @@ gfxPlatform::CreateSimilarSoftwareDrawTarget(DrawTarget* aDT,
 }
 
 /* static */ already_AddRefed<DrawTarget>
-gfxPlatform::CreateDrawTargetForData(unsigned char* aData, const IntSize& aSize, int32_t aStride, SurfaceFormat aFormat)
+gfxPlatform::CreateDrawTargetForData(unsigned char* aData,
+                                     const IntSize& aSize,
+                                     int32_t aStride,
+                                     SurfaceFormat aFormat,
+                                     bool aUninitialized)
 {
   BackendType backendType = gfxVars::ContentBackend();
   NS_ASSERTION(backendType != BackendType::NONE, "No backend.");
@@ -1484,7 +1488,8 @@ gfxPlatform::CreateDrawTargetForData(unsigned char* aData, const IntSize& aSize,
 
   RefPtr<DrawTarget> dt = Factory::CreateDrawTargetForData(backendType,
                                                            aData, aSize,
-                                                           aStride, aFormat);
+                                                           aStride, aFormat,
+                                                           aUninitialized);
 
   return dt.forget();
 }

gfx/thebes/gfxPlatform.h

@@ -241,8 +241,11 @@ public:
       CreateSimilarSoftwareDrawTarget(DrawTarget* aDT, const IntSize &aSize, mozilla::gfx::SurfaceFormat aFormat);
 
     static already_AddRefed<DrawTarget>
-      CreateDrawTargetForData(unsigned char* aData, const mozilla::gfx::IntSize& aSize, 
-                              int32_t aStride, mozilla::gfx::SurfaceFormat aFormat);
+      CreateDrawTargetForData(unsigned char* aData,
+                              const mozilla::gfx::IntSize& aSize, 
+                              int32_t aStride,
+                              mozilla::gfx::SurfaceFormat aFormat,
+                              bool aUninitialized = false);
 
     /**
      * Returns true if rendering to data surfaces produces the same results as