Use a rect instead of a region for UpdateDestinationFrom (bug 1409871 part 15, r=nical)

UpdateDestinationFrom actually only uses a rect, so it's best to not be
misleading and force the clients of it to do the conversion.

MozReview-Commit-ID: EsUv3apqnku

--HG--
extra : rebase_source : 02fdd8f7ede0e1c4712a721e14a4ad809b6dff14

gfx/layers/RotatedBuffer.cpp

@@ -240,11 +240,11 @@ RotatedBuffer::DrawTo(PaintedLayer* aLayer,
 
 void
 RotatedBuffer::UpdateDestinationFrom(const RotatedBuffer& aSource,
-                                     const nsIntRegion& aUpdateRegion)
+                                     const gfx::IntRect& aUpdateRect)
 {
   DrawIterator iter;
   while (DrawTarget* destDT =
-    BorrowDrawTargetForQuadrantUpdate(aUpdateRegion.GetBounds(), BUFFER_BLACK, &iter)) {
+    BorrowDrawTargetForQuadrantUpdate(aUpdateRect, BUFFER_BLACK, &iter)) {
     bool isClippingCheap = IsClippingCheap(destDT, iter.mDrawRegion);
     if (isClippingCheap) {
       gfxUtils::ClipToRegion(destDT, iter.mDrawRegion);
@@ -262,7 +262,7 @@ RotatedBuffer::UpdateDestinationFrom(const RotatedBuffer& aSource,
   if (aSource.HaveBufferOnWhite() && HaveBufferOnWhite()) {
     DrawIterator whiteIter;
     while (DrawTarget* destDT =
-      BorrowDrawTargetForQuadrantUpdate(aUpdateRegion.GetBounds(), BUFFER_WHITE, &whiteIter)) {
+      BorrowDrawTargetForQuadrantUpdate(aUpdateRect, BUFFER_WHITE, &whiteIter)) {
       bool isClippingCheap = IsClippingCheap(destDT, whiteIter.mDrawRegion);
       if (isClippingCheap) {
         gfxUtils::ClipToRegion(destDT, whiteIter.mDrawRegion);

gfx/layers/RotatedBuffer.h

@@ -118,7 +118,7 @@ public:
    * of a source rotated buffer.
    */
   void UpdateDestinationFrom(const RotatedBuffer& aSource,
-                             const nsIntRegion& aUpdateRegion);
+                             const gfx::IntRect& aUpdateRect);
 
   /**
    * A draw iterator is used to keep track of which quadrant of a rotated

gfx/layers/client/ContentClient.cpp

@@ -215,7 +215,7 @@ ContentClient::BeginPaintBuffer(PaintedLayer* aLayer,
   // If needed, copy the old buffer over to the new one
   if (newBuffer) {
     if (mBuffer) {
-      newBuffer->UpdateDestinationFrom(*mBuffer, nsIntRegion(newBuffer->BufferRect()));
+      newBuffer->UpdateDestinationFrom(*mBuffer, newBuffer->BufferRect());
     }
 
     // Ensure our reference to the front buffer is released
@@ -931,7 +931,7 @@ ContentClientDoubleBuffered::FinalizeFrame(const nsIntRegion& aRegionToDraw)
   }
 
   if (mFrontBuffer->Lock(OpenMode::OPEN_READ_ONLY)) {
-    mBuffer->UpdateDestinationFrom(*mFrontBuffer, updateRegion);
+    mBuffer->UpdateDestinationFrom(*mFrontBuffer, updateRegion.GetBounds());
     mFrontBuffer->Unlock();
   }
 }