DO NOT MERGE Set the initial scroll position for RTL.

 Bug 5268793
 Webkit knows about the correct initial position for web pages.
 On initial show, scroll to the webkit position.

 Cherry-picked from master CL: I2537b84a

 External WebKit CL: I6a91b97f

Change-Id: I2537b84a30a26a79a8a0f23fe62b9ed757f9c5a4

Author: George Mount

core/java/android/webkit/BrowserFrame.java

@@ -1404,4 +1404,17 @@ public void stopLoading() {
     native void nativeSslClientCert(int handle,
                                     byte[] pkcs8EncodedPrivateKey,
                                     byte[][] asn1DerEncodedCertificateChain);
+
+    /**
+     * Returns true when the contents of the frame is an RTL or vertical-rl
+     * page. This is used for determining whether a frame should be initially
+     * scrolled right-most as opposed to left-most.
+     * @return true when the frame should be initially scrolled right-most
+     * based on the text direction and writing mode.
+     */
+    /* package */ boolean getShouldStartScrolledRight() {
+        return nativeGetShouldStartScrolledRight(mNativeFrame);
+    }
+
+    private native boolean nativeGetShouldStartScrolledRight(int nativeBrowserFrame);
 }

core/java/android/webkit/WebView.java

@@ -8716,27 +8716,6 @@ void setNewPicture(final WebViewCore.DrawData draw, boolean updateBaseLayer) {
                     isPictureAfterFirstLayout, registerPageSwapCallback);
         }
         final Point viewSize = draw.mViewSize;
-        if (isPictureAfterFirstLayout) {
-            // Reset the last sent data here since dealing with new page.
-            mLastWidthSent = 0;
-            mZoomManager.onFirstLayout(draw);
-            if (!mDrawHistory) {
-                // Do not send the scroll event for this particular
-                // scroll message.  Note that a scroll event may
-                // still be fired if the user scrolls before the
-                // message can be handled.
-                mSendScrollEvent = false;
-                setContentScrollTo(viewState.mScrollX, viewState.mScrollY);
-                mSendScrollEvent = true;
-
-                // As we are on a new page, remove the WebTextView. This
-                // is necessary for page loads driven by webkit, and in
-                // particular when the user was on a password field, so
-                // the WebTextView was visible.
-                clearTextEntry();
-            }
-        }
-
         // We update the layout (i.e. request a layout from the
         // view system) if the last view size that we sent to
         // WebCore matches the view size of the picture we just
@@ -8749,7 +8728,25 @@ void setNewPicture(final WebViewCore.DrawData draw, boolean updateBaseLayer) {
         mSendScrollEvent = false;
         recordNewContentSize(draw.mContentSize.x,
                 draw.mContentSize.y, updateLayout);
+
+        if (isPictureAfterFirstLayout) {
+            // Reset the last sent data here since dealing with new page.
+            mLastWidthSent = 0;
+            mZoomManager.onFirstLayout(draw);
+            int scrollX = viewState.mShouldStartScrolledRight
+                    ? getContentWidth() : viewState.mScrollX;
+            int scrollY = viewState.mScrollY;
+            setContentScrollTo(scrollX, scrollY);
+            if (!mDrawHistory) {
+                // As we are on a new page, remove the WebTextView. This
+                // is necessary for page loads driven by webkit, and in
+                // particular when the user was on a password field, so
+                // the WebTextView was visible.
+                clearTextEntry();
+            }
+        }
         mSendScrollEvent = true;
+
         if (DebugFlags.WEB_VIEW) {
             Rect b = draw.mInvalRegion.getBounds();
             Log.v(LOGTAG, "NEW_PICTURE_MSG_ID {" +

core/java/android/webkit/WebViewCore.java

@@ -1982,6 +1982,7 @@ static class ViewState {
         int mScrollY;
         boolean mMobileSite;
         boolean mIsRestored;
+        boolean mShouldStartScrolledRight;
     }
 
     static class DrawData {
@@ -2382,6 +2383,7 @@ private void setupViewport(boolean updateViewState) {
             viewState.mMobileSite = false;
             // for non-mobile site, we don't need minPrefWidth, set it as 0
             viewState.mScrollX = 0;
+            viewState.mShouldStartScrolledRight = false;
             Message.obtain(mWebView.mPrivateHandler,
                     WebView.UPDATE_ZOOM_RANGE, viewState).sendToTarget();
             return;
@@ -2412,6 +2414,11 @@ private void setupViewport(boolean updateViewState) {
         mInitialViewState.mDefaultScale = adjust;
         mInitialViewState.mScrollX = mRestoredX;
         mInitialViewState.mScrollY = mRestoredY;
+        mInitialViewState.mShouldStartScrolledRight = (mRestoredX == 0)
+                && (mRestoredY == 0)
+                && (mBrowserFrame != null)
+                && mBrowserFrame.getShouldStartScrolledRight();
+
         mInitialViewState.mMobileSite = (0 == mViewportWidth);
         if (mIsRestored) {
             mInitialViewState.mIsRestored = true;