DO NOT MERGE Fix memory leak when creating SkBitmapProcShader

cherry pick from AOSP/master

A SkShader is ref counted, but the first but unref() was
never called for the local reference in
PlatformGraphicsContextSkia::drawBitmapPattern().

Change-Id: I2d1a2e95eeaf479e332a2dbd4e1e9f1b8baac0f7

Source/WebCore/platform/graphics/android/context/PlatformGraphicsContextSkia.cpp

@@ -239,7 +239,7 @@ void PlatformGraphicsContextSkia::drawBitmapPattern(
     SkPaint paint;
     setupPaintCommon(&paint);
     paint.setAlpha(getNormalizedAlpha());
-    paint.setShader(shader);
+    paint.setShader(shader)->unref();
     paint.setXfermodeMode(WebCoreCompositeToSkiaComposite(compositeOp));
     fixPaintForBitmapsThatMaySeam(&paint);
     mCanvas->drawRect(destRect, paint);