[Checkstyle] Enable boolean simplification and fix up some issues.

content/public/android/java/src/org/chromium/content/browser/ContentReadbackHandler.java

 // Copyright 2014 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.
 
 package org.chromium.content.browser;
 
 import android.graphics.Bitmap;
 import android.graphics.Rect;
 import android.util.SparseArray;
 
@@ skipping 104 matching lines @@
     }
 
     /**
      * Implemented by the owner of this class to signal whether readback is possible or not.
      * @return Whether readback is possible or not.
      */
     protected abstract boolean readyForReadback();
 
     private native long nativeInit();
     private native void nativeDestroy(long nativeContentReadbackHandler);
-    private native void nativeGetContentBitmap(long nativeContentReadbackHandler, int readback_id,
+    private native void nativeGetContentBitmap(long nativeContentReadbackHandler, int readbackId,
             float scale, Bitmap.Config config, float x, float y, float width, float height,
             Object contentViewCore);
     private native void nativeGetCompositorBitmap(long nativeContentReadbackHandler,
-            int readback_id, long nativeWindowAndroid);
+            int readbackId, long nativeWindowAndroid);
 }