Implement clearView to match classic

android_webview/java/src/org/chromium/android_webview/AwContents.java

 // Copyright 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.
 
 package org.chromium.android_webview;
 
 import android.content.pm.PackageManager;
 import android.content.res.Configuration;
 import android.graphics.Bitmap;
 import android.graphics.Canvas;
@@ skipping 162 matching lines @@
 
     private DefaultVideoPosterRequestHandler mDefaultVideoPosterRequestHandler;
 
     // Bound method for suppling Picture instances to the AwContentsClient. Will be null if the
     // picture listener API has not yet been enabled, or if it is using invalidation-only mode.
     private Callable<Picture> mPictureListenerContentProvider;
 
     private boolean mContainerViewFocused;
     private boolean mWindowFocused;
 
+    private boolean mClearViewActive;
+    private boolean mPictureListenerEnabled;
+
     private AwAutofillManagerDelegate mAwAutofillManagerDelegate;
 
     private static final class DestroyRunnable implements Runnable {
         private int mNativeAwContents;
         private DestroyRunnable(int nativeAwContents) {
             mNativeAwContents = nativeAwContents;
         }
         @Override
         public void run() {
             // This is a no-op if not currently attached.
@@ skipping 494 matching lines @@
     // Only valid within onDraw().
     private final Rect mClipBoundsTemporary = new Rect();
 
     public void onDraw(Canvas canvas) {
         if (mNativeAwContents == 0) {
             canvas.drawColor(getEffectiveBackgroundColor());
             return;
         }
 
         mScrollOffsetManager.syncScrollOffsetFromOnDraw();
+        canvas.getClipBounds(mClipBoundsTemporary);
 
-        canvas.getClipBounds(mClipBoundsTemporary);
-        if (!nativeOnDraw(mNativeAwContents, canvas, canvas.isHardwareAccelerated(),
-                    mContainerView.getScrollX(), mContainerView.getScrollY(),
-                    mClipBoundsTemporary.left, mClipBoundsTemporary.top,
-                    mClipBoundsTemporary.right, mClipBoundsTemporary.bottom)) {
+        if (mClearViewActive) {
+            canvas.drawColor(getEffectiveBackgroundColor());

[boliu, 2013/09/20 20:55:49]

Documentation says draws white background, not whatever was set by app. We
should do what it does, not what it says, did you double check what old webview
did?

[Kristian Monsen, 2013/09/20 21:15:17]

Classic actually does the background color as well. This is just insane. Oh
well.

+        } else if (!nativeOnDraw(mNativeAwContents, canvas, canvas.isHardwareAccelerated(),
+                mContainerView.getScrollX(), mContainerView.getScrollY(),
+                mClipBoundsTemporary.left, mClipBoundsTemporary.top,
+                mClipBoundsTemporary.right, mClipBoundsTemporary.bottom)) {
             Log.w(TAG, "nativeOnDraw failed; clearing to background color.");
             canvas.drawColor(getEffectiveBackgroundColor());
         }
 
         if (mOverScrollGlow != null && mOverScrollGlow.drawEdgeGlows(canvas,
                     mScrollOffsetManager.computeMaximumHorizontalScrollOffset(),
                     mScrollOffsetManager.computeMaximumVerticalScrollOffset())) {
             mContainerView.invalidate();

[boliu, 2013/08/16 23:04:55]

Badness right there...should let InProcessViewRenderer know. Follow up clean up
way down the road I guess.

[mkosiba (inactive), 2013/08/19 16:14:14]

could you elaborate why invalidating the view is bad?

[boliu, 2013/08/19 16:21:49]

InProcessViewRenderer has logic for triggering/throttling invalidates and
scheduling the fallback tick. We should combine these and not have two
independent invalidate loops. So mostly a refactor issue.

Also not so bad post-jb, but should call AwContents.postInvalidateOnAnimation
instead of straight up invalidate as well.

[mkosiba (inactive), 2013/08/19 16:30:17]

yeath, but this isn't an invalidate for the contents, it's an invalidate for the
mOverScrollGlow which is drawing on top of what InProcessViewRenderer draws.

[Kristian Monsen, 2013/09/20 19:35:56]

Not related to this change :-)

         }
     }
 
     public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
         mLayoutSizer.onMeasure(widthMeasureSpec, heightMeasureSpec);
     }
 
     public int getContentHeightCss() {
         return (int) Math.ceil(mContentViewCore.getContentHeightCss());
     }
 
     public int getContentWidthCss() {
         return (int) Math.ceil(mContentViewCore.getContentWidthCss());
     }
 
     public Picture capturePicture() {
         return new AwPicture(nativeCapturePicture(mNativeAwContents,
                     mScrollOffsetManager.computeHorizontalScrollRange(),
                     mScrollOffsetManager.computeVerticalScrollRange()));
     }
 
+    public void clearView() {
+        mClearViewActive = true;
+        syncOnNewPictureStateToNative();
+        mContainerView.invalidate();

[boliu, 2013/08/16 23:04:55]

Is this invalidate needed? Documentation only says next onDraw, doesn't say that
this has to cause a redraw.

Documentation also mentions something about onMeasure, but doesn't matter much
there.

Also should use postInvalidateOnAnimation lest we break ics upstream.

[Kristian Monsen, 2013/09/20 19:35:56]

The behavior we are trying to match is pretty much a direct redraw.

This works at least :-)

+    }
+
     /**
      * Enable the onNewPicture callback.
      * @param enabled Flag to enable the callback.
      * @param invalidationOnly Flag to call back only on invalidation without providing a picture.
      */
     public void enableOnNewPicture(boolean enabled, boolean invalidationOnly) {
         if (invalidationOnly) {
             mPictureListenerContentProvider = null;
         } else if (enabled && mPictureListenerContentProvider == null) {
             mPictureListenerContentProvider = new Callable<Picture>() {
                 @Override
                 public Picture call() {
                     return capturePicture();
                 }
             };
         }
-        nativeEnableOnNewPicture(mNativeAwContents, enabled);
+        mPictureListenerEnabled = enabled;
+        syncOnNewPictureStateToNative();
+    }
+
+    private void syncOnNewPictureStateToNative() {
+        nativeEnableOnNewPicture(mNativeAwContents, mPictureListenerEnabled || mClearViewActive);
     }
 
     public void findAllAsync(String searchString) {
         if (mNativeAwContents == 0) return;
         nativeFindAllAsync(mNativeAwContents, searchString);
     }
 
     public void findNext(boolean forward) {
         if (mNativeAwContents == 0) return;
         nativeFindNext(mNativeAwContents, forward);
@@ skipping 919 matching lines @@
     }
 
     @CalledByNative
     public void onFindResultReceived(int activeMatchOrdinal, int numberOfMatches,
             boolean isDoneCounting) {
         mContentsClient.onFindResultReceived(activeMatchOrdinal, numberOfMatches, isDoneCounting);
     }
 
     @CalledByNative
     public void onNewPicture() {
+        // Clear up any results from a previous clearView call
+        if (mClearViewActive) {
+            mClearViewActive = false;
+            mContainerView.invalidate();

[boliu, 2013/08/16 23:04:55]

Again is this needed? If cc activates, it should send invalidate pretty quickly
after that already.

[Kristian Monsen, 2013/09/20 19:35:56]

I think it is safe to keep it in? Remember this is very rarely called, so I
don't think we need to worry about performance concerns.

+            syncOnNewPictureStateToNative();
+        }
+
         // Don't call capturePicture() here but instead defer it until the posted task runs within
         // the callback helper, to avoid doubling back into the renderer compositor in the middle
         // of the notification it is sending up to here.
         mContentsClient.getCallbackHelper().postOnNewPicture(mPictureListenerContentProvider);
     }
 
     // Called as a result of nativeUpdateLastHitTestData.
     @CalledByNative
     private void updateHitTestData(
             int type, String extra, String href, String anchorText, String imgSrc) {
@@ skipping 170 matching lines @@
     private native void nativeFocusFirstNode(int nativeAwContents);
     private native void nativeSetBackgroundColor(int nativeAwContents, int color);
 
     private native int nativeGetAwDrawGLViewContext(int nativeAwContents);
     private native int nativeCapturePicture(int nativeAwContents, int width, int height);
     private native void nativeEnableOnNewPicture(int nativeAwContents, boolean enabled);
 
     private native void nativeInvokeGeolocationCallback(
             int nativeAwContents, boolean value, String requestingFrame);
 }