Support uploads of sub-rectangles of canvases to 2D and 3D textures.

third_party/WebKit/Source/platform/graphics/gpu/DrawingBuffer.cpp

Index: third_party/WebKit/Source/platform/graphics/gpu/DrawingBuffer.cpp
diff --git a/third_party/WebKit/Source/platform/graphics/gpu/DrawingBuffer.cpp b/third_party/WebKit/Source/platform/graphics/gpu/DrawingBuffer.cpp
index ea452ae747adb9a8e0457ed6de85f77db5de6c32..4023f3420e751291d9cc97de1e9cabda9e7bc632 100644
--- a/third_party/WebKit/Source/platform/graphics/gpu/DrawingBuffer.cpp
+++ b/third_party/WebKit/Source/platform/graphics/gpu/DrawingBuffer.cpp
@@ -674,6 +674,8 @@ bool DrawingBuffer::copyToPlatformTexture(gpu::gles2::GLES2Interface* gl,
                                           GLint level,
                                           bool premultiplyAlpha,
                                           bool flipY,
+                                          const IntPoint& destTextureOffset,
+                                          const IntRect& sourceSubRectangle,
                                           SourceDrawingBuffer sourceBuffer) {
   ScopedStateRestorer scopedStateRestorer(this);
 
@@ -719,9 +721,11 @@ bool DrawingBuffer::copyToPlatformTexture(gpu::gles2::GLES2Interface* gl,
   else if (m_wantAlphaChannel && !m_premultipliedAlpha && premultiplyAlpha)
     unpackPremultiplyAlphaNeeded = GL_TRUE;
 
-  gl->CopyTextureCHROMIUM(sourceTexture, texture, internalFormat, destType,
-                          flipY, unpackPremultiplyAlphaNeeded,
-                          unpackUnpremultiplyAlphaNeeded);
+  gl->CopySubTextureCHROMIUM(
+      sourceTexture, texture, destTextureOffset.x(), destTextureOffset.y(),
+      sourceSubRectangle.x(), sourceSubRectangle.y(),
+      sourceSubRectangle.width(), sourceSubRectangle.height(), flipY,
+      unpackPremultiplyAlphaNeeded, unpackUnpremultiplyAlphaNeeded);
 
   gl->DeleteTextures(1, &sourceTexture);