Add Java wrapper for RenderFrameHost

content/public/android/java/src/org/chromium/content/browser/webcontents/WebContentsImpl.java

Index: content/public/android/java/src/org/chromium/content/browser/webcontents/WebContentsImpl.java
diff --git a/content/public/android/java/src/org/chromium/content/browser/webcontents/WebContentsImpl.java b/content/public/android/java/src/org/chromium/content/browser/webcontents/WebContentsImpl.java
index b7dc50638047944bc3d5274028ae1d971e4d2ee6..715ef6405abb8031f200e19fc3adc49cba24135a 100644
--- a/content/public/android/java/src/org/chromium/content/browser/webcontents/WebContentsImpl.java
+++ b/content/public/android/java/src/org/chromium/content/browser/webcontents/WebContentsImpl.java
@@ -28,6 +28,7 @@ import org.chromium.content_public.browser.ImageDownloadCallback;
 import org.chromium.content_public.browser.JavaScriptCallback;
 import org.chromium.content_public.browser.MessagePortService;
 import org.chromium.content_public.browser.NavigationController;
+import org.chromium.content_public.browser.RenderFrameHost;
 import org.chromium.content_public.browser.SmartClipCallback;
 import org.chromium.content_public.browser.WebContents;
 import org.chromium.content_public.browser.WebContentsObserver;
@@ -167,6 +168,11 @@ import java.util.UUID;
     }
 
     @Override
+    public RenderFrameHost getMainFrame() {
+        return nativeGetMainFrame(mNativeWebContentsAndroid);
+    }
+
+    @Override
     public String getTitle() {
         return nativeGetTitle(mNativeWebContentsAndroid);
     }
@@ -540,6 +546,7 @@ import java.util.UUID;
 
     private static native WebContents nativeFromNativePtr(long webContentsAndroidPtr);
 
+    private native RenderFrameHost nativeGetMainFrame(long nativeWebContentsAndroid);
     private native String nativeGetTitle(long nativeWebContentsAndroid);
     private native String nativeGetVisibleURL(long nativeWebContentsAndroid);
     private native boolean nativeIsLoading(long nativeWebContentsAndroid);