Fix memory leak of "screen size bitmap" (e.g. 1.5M if 750x548)

that happened on *every page view* on OSX.

VSIZE/RSIZE now hovers around 500M/30M instead of growing to 1.3G/260M
within a few minutes.

Surprisingly, Chromium.app seems quite a bit snappier!

The essence of the change is that SkBitmap::setPixels() does NOT take
ownership of the pointer, whereas SkBitmap::allocPixels() both
allocates and owns.

Review URL: http://codereview.chromium.org/39307

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@11196 0039d316-1c4b-4281-b951-d872f2087c98

skia/ext/bitmap_platform_device_mac.cc

@@ -146,12 +146,11 @@ BitmapPlatformDeviceMac* BitmapPlatformDeviceMac::Create(CGContextRef context,
                                                          int width,
                                                          int height,
                                                          bool is_opaque) {
-  void* data = malloc(height * width * 4);
-  if (!data) return NULL;
-
   SkBitmap bitmap;
   bitmap.setConfig(SkBitmap::kARGB_8888_Config, width, height);
-  bitmap.setPixels(data);
+  if (bitmap.allocPixels() != true)
+    return NULL;
+  void* data = bitmap.getPixels();
 
   // Note: The Windows implementation clears the Bitmap later on.
   // This bears mentioning since removal of this line makes the
@@ -224,7 +223,7 @@ CGContextRef BitmapPlatformDeviceMac::GetBitmapContext() {
   return data_->GetBitmapContext();
 }
 
-void BitmapPlatformDeviceMac::setMatrixClip(const SkMatrix& transform, 
+void BitmapPlatformDeviceMac::setMatrixClip(const SkMatrix& transform,
                                             const SkRegion& region) {
   data_->SetMatrixClip(transform, region);
 }