[#2] Pass gfx structs by const ref (gfx::Rect, gfx::RectF)

cc/output/gl_renderer.cc

Index: cc/output/gl_renderer.cc
diff --git a/cc/output/gl_renderer.cc b/cc/output/gl_renderer.cc
index 5f443eefa531a48cecaaa34e07acde27de178392..28771a4007ce7a579bdd53949526e540de023695 100644
--- a/cc/output/gl_renderer.cc
+++ b/cc/output/gl_renderer.cc
@@ -2064,7 +2064,7 @@ void GLRenderer::DrawQuadGeometry(const DrawingFrame* frame,
 
 void GLRenderer::CopyTextureToFramebuffer(const DrawingFrame* frame,
                                           int texture_id,
-                                          gfx::Rect rect,
+                                          const gfx::Rect& rect,
                                           const gfx::Transform& draw_matrix,
                                           bool flip_vertically) {
   TexCoordPrecision tex_coord_precision = TexCoordPrecisionRequired(
@@ -2174,7 +2174,7 @@ void GLRenderer::EnsureBackbuffer() {
   is_backbuffer_discarded_ = false;
 }
 
-void GLRenderer::GetFramebufferPixels(void* pixels, gfx::Rect rect) {
+void GLRenderer::GetFramebufferPixels(void* pixels, const gfx::Rect& rect) {
   if (!pixels || rect.IsEmpty())
     return;
 
@@ -2193,7 +2193,7 @@ void GLRenderer::GetFramebufferPixels(void* pixels, gfx::Rect rect) {
 }
 
 void GLRenderer::GetFramebufferPixelsAsync(
-    gfx::Rect rect,
+    const gfx::Rect& rect,
     scoped_ptr<CopyOutputRequest> request) {
   DCHECK(!request->IsEmpty());
   if (request->IsEmpty())
@@ -2291,7 +2291,7 @@ void GLRenderer::GetFramebufferPixelsAsync(
 
 void GLRenderer::DoGetFramebufferPixels(
     uint8* dest_pixels,
-    gfx::Rect window_rect,
+    const gfx::Rect& window_rect,
     const AsyncGetFramebufferPixelsCleanupCallback& cleanup_callback) {
   DCHECK_GE(window_rect.x(), 0);
   DCHECK_GE(window_rect.y(), 0);
@@ -2474,7 +2474,7 @@ void GLRenderer::PassOnSkBitmap(scoped_ptr<SkBitmap> bitmap,
 
 void GLRenderer::GetFramebufferTexture(unsigned texture_id,
                                        ResourceFormat texture_format,
-                                       gfx::Rect window_rect) {
+                                       const gfx::Rect& window_rect) {
   DCHECK(texture_id);
   DCHECK_GE(window_rect.x(), 0);
   DCHECK_GE(window_rect.y(), 0);
@@ -2496,7 +2496,7 @@ void GLRenderer::GetFramebufferTexture(unsigned texture_id,
 
 bool GLRenderer::UseScopedTexture(DrawingFrame* frame,
                                   const ScopedResource* texture,
-                                  gfx::Rect viewport_rect) {
+                                  const gfx::Rect& viewport_rect) {
   DCHECK(texture->id());
   frame->current_render_pass = NULL;
   frame->current_texture = texture;
@@ -2518,7 +2518,7 @@ void GLRenderer::BindFramebufferToOutputSurface(DrawingFrame* frame) {
 
 bool GLRenderer::BindFramebufferToTexture(DrawingFrame* frame,
                                           const ScopedResource* texture,
-                                          gfx::Rect target_rect) {
+                                          const gfx::Rect& target_rect) {
   DCHECK(texture->id());
 
   current_framebuffer_lock_.reset();
@@ -2542,7 +2542,7 @@ bool GLRenderer::BindFramebufferToTexture(DrawingFrame* frame,
   return true;
 }
 
-void GLRenderer::SetScissorTestRect(gfx::Rect scissor_rect) {
+void GLRenderer::SetScissorTestRect(const gfx::Rect& scissor_rect) {
   EnsureScissorTestEnabled();
 
   // Don't unnecessarily ask the context to change the scissor, because it
@@ -2561,7 +2561,7 @@ void GLRenderer::SetScissorTestRect(gfx::Rect scissor_rect) {
   scissor_rect_needs_reset_ = false;
 }
 
-void GLRenderer::SetDrawViewport(gfx::Rect window_space_viewport) {
+void GLRenderer::SetDrawViewport(const gfx::Rect& window_space_viewport) {
   viewport_ = window_space_viewport;
   GLC(gl_,
       gl_->Viewport(window_space_viewport.x(),