Merge change 4737 into donut

* changes:
  Add prepareToDraw() to Bitmap for fixing http://b/issue?id=1907995.

api/current.xml

@@ -47001,6 +47001,17 @@
  visibility="public"
 >
 </method>
+<method name="prepareToDraw"
+ return="void"
+ abstract="false"
+ native="false"
+ synchronized="false"
+ static="false"
+ final="false"
+ deprecated="not deprecated"
+ visibility="public"
+>
+</method>
 <method name="recycle"
  return="void"
  abstract="false"

core/jni/android/graphics/Bitmap.cpp

@@ -519,6 +519,11 @@ static void Bitmap_copyPixelsFromBuffer(JNIEnv* env, jobject,
     }
 }
 
+static void Bitmap_prepareToDraw(JNIEnv* env, jobject, SkBitmap* bitmap) {
+    bitmap->lockPixels();
+    bitmap->unlockPixels();
+}
+
 ///////////////////////////////////////////////////////////////////////////////
 
 #include <android_runtime/AndroidRuntime.h>
@@ -552,7 +557,8 @@ static JNINativeMethod gBitmapMethods[] = {
     {   "nativeCopyPixelsToBuffer", "(ILjava/nio/Buffer;)V",
                                             (void*)Bitmap_copyPixelsToBuffer },
     {   "nativeCopyPixelsFromBuffer", "(ILjava/nio/Buffer;)V",
-                                            (void*)Bitmap_copyPixelsFromBuffer }
+                                            (void*)Bitmap_copyPixelsFromBuffer },
+    {   "nativePrepareToDraw",      "(I)V", (void*)Bitmap_prepareToDraw }
 };
 
 #define kClassPathName  "android/graphics/Bitmap"

graphics/java/android/graphics/Bitmap.java

@@ -16,14 +16,14 @@
 
 package android.graphics;
 
-import android.os.Parcelable;
 import android.os.Parcel;
+import android.os.Parcelable;
 
+import java.io.OutputStream;
 import java.nio.Buffer;
 import java.nio.ByteBuffer;
-import java.nio.ShortBuffer;
 import java.nio.IntBuffer;
-import java.io.OutputStream;
+import java.nio.ShortBuffer;
 
 public final class Bitmap implements Parcelable {
     /**
@@ -917,6 +917,22 @@ public final class Bitmap implements Parcelable {
         return bm;
     }
 
+    /**
+     * Rebuilds any caches associated with the bitmap that are used for
+     * drawing it. In the case of purgeable bitmaps, this call will attempt to
+     * ensure that the pixels have been decoded.
+     * If this is called on more than one bitmap in sequence, the priority is
+     * given in LRU order (i.e. the last bitmap called will be given highest
+     * priority).
+     *
+     * For bitmaps with no associated caches, this call is effectively a no-op,
+     * and therefore is harmless.
+     */
+    public void prepareToDraw() {
+        nativePrepareToDraw(mNativeBitmap);
+    }
+
+    @Override
     protected void finalize() throws Throwable {
         try {
             nativeDestructor(mNativeBitmap);
@@ -969,6 +985,8 @@ public final class Bitmap implements Parcelable {
                                                     int nativePaint,
                                                     int[] offsetXY);
 
+    private static native void nativePrepareToDraw(int nativeBitmap);
+
     /* package */ final int ni() {
         return mNativeBitmap;
     }