SkBitmap move

Running `Release/dm --gpu 0`, the number of times we call
	SkBitmap::operator=(const SkBitmap&)
(which refs the pixelref) is reduced from ~214929 to ~214626.

Review URL: https://codereview.chromium.org/1514503004

1 files changed, 14 insertions, 2 deletions

diff --git a/include/core/SkBitmap.h b/include/core/SkBitmap.h
index cf1c4c77f2..a81e03eefa 100644
--- a/include/core/SkBitmap.h
+++ b/include/core/SkBitmap.h
@@ -54,12 +54,24 @@ public:
      */
     SkBitmap(const SkBitmap& src);
 
+    /**
+     *  Copy the settings from the src into this bitmap. If the src has pixels
+     *  allocated, ownership of the pixels will be taken.
+     */
+    SkBitmap(SkBitmap&& src);
+
     ~SkBitmap();
 
-    /** Copies the src bitmap into this bitmap. Ownership of the src bitmap's pixels remains
-        with the src bitmap.
+    /** Copies the src bitmap into this bitmap. Ownership of the src
+        bitmap's pixels is shared with the src bitmap.
     */
     SkBitmap& operator=(const SkBitmap& src);
+
+    /** Copies the src bitmap into this bitmap. Takes ownership of the src
+        bitmap's pixels.
+    */
+    SkBitmap& operator=(SkBitmap&& src);
+
     /** Swap the fields of the two bitmaps. This routine is guaranteed to never fail or throw.
     */
     //  This method is not exported to java.