ui: Add sub region copy support to GLImage::CopyTexImage.

gpu/command_buffer/service/gles2_cmd_decoder.cc

Index: gpu/command_buffer/service/gles2_cmd_decoder.cc
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder.cc b/gpu/command_buffer/service/gles2_cmd_decoder.cc
index 38c99ba4a68f5b08c641f753a71eed1785aca6d0..bce5894767ac64c621ce87f76be71bc4d35f3b1d 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.cc
@@ -11873,8 +11873,10 @@ void GLES2DecoderImpl::DoCopyTextureCHROMIUM(GLenum target,
       unpack_premultiply_alpha_ ^ unpack_unpremultiply_alpha_;
   if (image && !unpack_flip_y_ && !unpack_premultiply_alpha_change) {
     glBindTexture(GL_TEXTURE_2D, dest_texture->service_id());
-    if (image->CopyTexImage(GL_TEXTURE_2D))
+    if (image->CopyTexSubImage(GL_TEXTURE_2D, gfx::Point(0, 0),
+                               gfx::Rect(0, 0, source_width, source_height))) {
       return;
+    }
   }
 
   DoWillUseTexImageIfNeeded(source_texture, source_texture->target());
@@ -12010,11 +12012,12 @@ void GLES2DecoderImpl::DoCopySubTextureCHROMIUM(GLenum target,
   // Try using GLImage::CopyTexSubImage when possible.
   bool unpack_premultiply_alpha_change =
       unpack_premultiply_alpha_ ^ unpack_unpremultiply_alpha_;
-  if (image && !unpack_flip_y_ && !unpack_premultiply_alpha_change &&
-      !xoffset && !yoffset) {
+  if (image && !unpack_flip_y_ && !unpack_premultiply_alpha_change) {
     glBindTexture(GL_TEXTURE_2D, dest_texture->service_id());
-    if (image->CopyTexImage(GL_TEXTURE_2D))
+    if (image->CopyTexSubImage(GL_TEXTURE_2D, gfx::Point(xoffset, yoffset),
+                               gfx::Rect(0, 0, source_width, source_height))) {
       return;
+    }
   }
 
   DoWillUseTexImageIfNeeded(source_texture, source_texture->target());