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, 10 insertions, 0 deletions

diff --git a/src/core/SkBitmap.cpp b/src/core/SkBitmap.cpp
index 8997f2b014..661dca3ea5 100644
--- a/src/core/SkBitmap.cpp
+++ b/src/core/SkBitmap.cpp
@@ -39,6 +39,8 @@ SkBitmap::SkBitmap(const SkBitmap& src) {
     SkDEBUGCODE(this->validate();)
 }
 
+SkBitmap::SkBitmap(SkBitmap&& other) : SkBitmap() { this->swap(other); }
+
 SkBitmap::~SkBitmap() {
     SkDEBUGCODE(this->validate();)
     this->freePixels();
@@ -72,6 +74,14 @@ SkBitmap& SkBitmap::operator=(const SkBitmap& src) {
     return *this;
 }
 
+SkBitmap& SkBitmap::operator=(SkBitmap&& other) {
+    if (this != &other) {
+        this->swap(other);
+        other.reset();
+    }
+    return *this;
+}
+
 void SkBitmap::swap(SkBitmap& other) {
     SkTSwap(fColorTable, other.fColorTable);
     SkTSwap(fPixelRef, other.fPixelRef);