Add overscroll edge effect animations for Android.

ui/gfx/android/java_bitmap.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/gfx/android/java_bitmap.h"
 
 #include <android/bitmap.h>
 
 #include "base/logging.h"
 #include "jni/BitmapHelper_jni.h"
@@ skipping 50 matching lines @@
 }
 
 static ScopedJavaLocalRef<jobject> CreateJavaBitmapFromResource(
     const char* name) {
   JNIEnv* env = AttachCurrentThread();
   ScopedJavaLocalRef<jstring> jname(env, env->NewStringUTF(name));
   return ui::Java_BitmapHelper_decodeDrawableResource(env, jname.obj());
 }
 
 static SkBitmap ConvertToSkBitmap(ScopedJavaLocalRef<jobject> jbitmap) {
+  if (jbitmap.is_null())
+    return SkBitmap();
+
   JavaBitmap src_lock(jbitmap.obj());
   DCHECK_EQ(src_lock.format(), ANDROID_BITMAP_FORMAT_RGBA_8888);
 
   gfx::Size src_size = src_lock.size();
 
   SkBitmap skbitmap;
   skbitmap.setConfig(SkBitmap::kARGB_8888_Config,
       src_size.width(), src_size.height(), src_lock.stride());
   skbitmap.allocPixels();
   SkAutoLockPixels dst_lock(skbitmap);
 
   void* src_pixels = src_lock.pixels();
   void* dst_pixels = skbitmap.getPixels();
 
   memcpy(dst_pixels, src_pixels, skbitmap.getSize());
 
   return skbitmap;
 }
 
 SkBitmap CreateSkBitmapFromResource(const char* name) {
   return ConvertToSkBitmap(CreateJavaBitmapFromResource(name));
 }
 
 }  //  namespace gfx