[chromium] Pass SkBitmap by reference in WebNinePatchLayer::setBitmap and refactor

Although passing SkBitmap by value doesn't copy the underlying pixels, it indeed
involves memcpy (~64 bytes to be precise) to replicate the settings from the
other bitmap in the copy constructor.

This overhead, albeit minor, can be avoided by passing SkBitmap as reference.

R=jamesr@chromium.org

Review URL: https://codereview.chromium.org/597553002

Cr-Commit-Position: refs/heads/master@{#296330}

cc/blink/web_nine_patch_layer_impl.cc

@@ -34,7 +34,7 @@ void WebNinePatchLayerImpl::setBitmap(SkBitmap bitmap,
                            bitmap.height() - aperture.height));
 }
 
-void WebNinePatchLayerImpl::setBitmap(SkBitmap bitmap) {
+void WebNinePatchLayerImpl::setBitmap(const SkBitmap& bitmap) {
   cc::NinePatchLayer* nine_patch =
       static_cast<cc::NinePatchLayer*>(layer_->layer());
   nine_patch->SetBitmap(bitmap);
@@ -52,10 +52,4 @@ void WebNinePatchLayerImpl::setBorder(const blink::WebRect& border) {
   nine_patch->SetBorder(gfx::Rect(border));
 }
 
-void WebNinePatchLayerImpl::setFillCenter(bool fill_center) {
-  cc::NinePatchLayer* nine_patch =
-      static_cast<cc::NinePatchLayer*>(layer_->layer());
-  nine_patch->SetFillCenter(fill_center);
-}
-
 }  // namespace cc_blink

cc/blink/web_nine_patch_layer_impl.h

@@ -22,13 +22,12 @@ class WebNinePatchLayerImpl : public blink::WebNinePatchLayer {
   // blink::WebNinePatchLayer implementation.
   virtual blink::WebLayer* layer();
 
-  // TODO(ccameron): Remove setBitmap(SkBitmap, blink::WebRect) in favor of
-  // setBitmap(), setAperture(), and setBorder();
+  // TODO(vivekg): Remove setBitmap(SkBitmap, blink::WebRect) once blink side
+  // CL, http://crrev.com/594193002 lands
   virtual void setBitmap(SkBitmap bitmap, const blink::WebRect& aperture);
-  virtual void setBitmap(SkBitmap bitmap);
+  virtual void setBitmap(const SkBitmap& bitmap);
   virtual void setAperture(const blink::WebRect& aperture);
   virtual void setBorder(const blink::WebRect& border);
-  virtual void setFillCenter(bool fill_center);
 
  private:
   scoped_ptr<WebLayerImpl> layer_;