Revert of [#7] Pass gfx structs by const ref (gfx::Size)

cc/output/gl_renderer.cc

 // Copyright 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/output/gl_renderer.h"
 
 #include <algorithm>
 #include <limits>
 #include <set>
 #include <string>
@@ skipping 2384 matching lines @@
   }
 
   EnforceMemoryPolicy();
 }
 
 void GLRenderer::FinishedReadback(
     const AsyncGetFramebufferPixelsCleanupCallback& cleanup_callback,
     unsigned source_buffer,
     unsigned query,
     uint8* dest_pixels,
-    const gfx::Size& size) {
+    gfx::Size size) {
   DCHECK(!pending_async_read_pixels_.empty());
 
   if (query != 0) {
     GLC(gl_, gl_->DeleteQueriesEXT(1, &query));
   }
 
   PendingAsyncReadPixels* current_read = pending_async_read_pixels_.back();
   // Make sure we service the readbacks in order.
   DCHECK_EQ(source_buffer, current_read->buffer);
 
@@ skipping 587 matching lines @@
   is_scissor_enabled_ = false;
   GLC(gl_, gl_->Disable(GL_SCISSOR_TEST));
   scissor_rect_needs_reset_ = true;
 }
 
 bool GLRenderer::IsContextLost() {
   return output_surface_->context_provider()->IsContextLost();
 }
 
 }  // namespace cc