[Android] Move zoom controls management into WebView

android_webview/java/src/org/chromium/android_webview/AwZoomControls.java

Index: android_webview/java/src/org/chromium/android_webview/AwZoomControls.java
diff --git a/android_webview/java/src/org/chromium/android_webview/AwZoomControls.java b/android_webview/java/src/org/chromium/android_webview/AwZoomControls.java
new file mode 100644
index 0000000000000000000000000000000000000000..9579d50f509612402f04c2d7340e9a4ed774254c
--- /dev/null
+++ b/android_webview/java/src/org/chromium/android_webview/AwZoomControls.java
@@ -0,0 +1,98 @@
+// Copyright (c) 2013 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.view.Gravity;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.FrameLayout;
+import android.widget.ZoomButtonsController;
+import org.chromium.content.browser.ContentViewCore.ZoomControlsDelegate;
+
+class AwZoomControls implements ZoomControlsDelegate {
+
+    private AwContents mAwContents;
+    private ZoomButtonsController mZoomButtonsController;
+
+    AwZoomControls(AwContents awContents) {
+        mAwContents = awContents;
+    }
+
+    @Override
+    public void invokeZoomPicker() {
+        ZoomButtonsController zoomControls = getZoomControls();
+        if (zoomControls != null && !zoomControls.isVisible()) {

[joth, 2013/05/03 19:32:43]

maybe we should call setVisible(true) even if they're already visible, as this
has side effect of refreshing the delayed hide timer inside
ZoomButtonsController.dismissControlsDelay ?

[mnaganov (inactive), 2013/05/07 09:55:44]

Right, it seems better to omit this check. Also, the legacy ZoomManager doesn't
have one.

+            zoomControls.setVisible(true);

[joth, 2013/05/03 19:32:43]

do we need to update the individual button states too?  - updateZoomControls()

[mnaganov (inactive), 2013/05/07 09:55:44]

ZoomButtonsController calls ZoomListener's onVisibilityChanged, which calls
updateZoomControls.

+        }
+    }
+
+    @Override
+    public void dismissZoomPicker() {
+        ZoomButtonsController zoomControls = getZoomControls();
+        if (zoomControls != null && zoomControls.isVisible()) {
+            zoomControls.setVisible(false);
+        }
+    }
+
+    @Override
+    public void updateZoomControls() {
+        if (mZoomButtonsController == null) return;

[joth, 2013/05/03 19:32:43]

not obvious why you use mZoomButtonsController here but getZoomControls() above?
maybe comment one or other.

[mnaganov (inactive), 2013/05/07 09:55:44]

Yes, that's a strange assymetry. Changed to getZoomControls() here.

+        boolean canZoomIn = mAwContents.canZoomIn();
+        boolean canZoomOut = mAwContents.canZoomOut();
+        if (!canZoomIn && !canZoomOut) {
+            // Hide the zoom in and out buttons if the page cannot zoom
+            mZoomButtonsController.getZoomControls().setVisibility(View.GONE);
+        } else {
+            // Set each one individually, as a page may be able to zoom in or out
+            mZoomButtonsController.setZoomInEnabled(canZoomIn);
+            mZoomButtonsController.setZoomOutEnabled(canZoomOut);

[joth, 2013/05/03 19:32:43]

how do these settings nest? do we need to call 
mZoomButtonsController.getZoomControls().setVisibility(VISISBLE) here too, or
does enabling either button automatically cause the controls to be shown?

[mnaganov (inactive), 2013/05/07 09:55:44]

Visibility and button status are orthogonal. But we don't want to show controls
from here. Recall that the controls are not always shown. They appear for a
short interval after a scroll event. Thus, forcing them to show from here is
undesired.

+        }
+    }
+
+    // This method is used in tests. It doesn't modify the state of zoom controls.
+    View getZoomControlsViewForTest() {
+        return mZoomButtonsController != null ? mZoomButtonsController.getZoomControls() : null;
+    }
+
+    private ZoomButtonsController getZoomControls() {

[joth, 2013/05/03 19:32:43]

getZoomController() ? Maybe comment when to use this vs. mZoomButtonsController
directly. (Or make the fn name reflect the side effects it has)

[mnaganov (inactive), 2013/05/07 09:55:44]

Renamed. Added a comment on the field to advice to use getZoomController where
possible.

+        if (mZoomButtonsController == null &&
+            mAwContents.getSettings().shouldDisplayZoomControls()) {
+            mZoomButtonsController = new ZoomButtonsController(
+                    mAwContents.getContentViewCore().getContainerView());
+            mZoomButtonsController.setOnZoomListener(new ZoomListener());
+            // ZoomButtonsController positions the buttons at the bottom, but in
+            // the middle. Change their layout parameters so they appear on the
+            // right.
+            View controls = mZoomButtonsController.getZoomControls();
+            ViewGroup.LayoutParams params = controls.getLayoutParams();
+            if (params instanceof FrameLayout.LayoutParams) {
+                ((FrameLayout.LayoutParams) params).gravity = Gravity.RIGHT;
+            }
+        }
+        return mZoomButtonsController;
+    }
+
+    private class ZoomListener implements ZoomButtonsController.OnZoomListener {
+        @Override
+        public void onVisibilityChanged(boolean visible) {
+            if (visible) {
+                // Bring back the hidden zoom controls.
+                mZoomButtonsController.getZoomControls().setVisibility(View.VISIBLE);
+                updateZoomControls();
+            }
+        }
+
+        @Override
+        public void onZoom(boolean zoomIn) {
+            if (zoomIn) {
+                mAwContents.zoomIn();
+            } else {
+                mAwContents.zoomOut();
+            }
+            // ContentView will call updateZoomControls after its current page scale
+            // is got updated from the native code.
+        }
+    }
+}