webview: fix zoom control updating

As part of
https://chromium-review.googlesource.com/c/chromium/src/+/2225548
I removed an override of onScrollOffsetOrExtentChanged. It turns out
the code was relying on this to be called when the scale factor
changed so that the zoom-controls could be updated.

The fix is to update the zoom-controls when the scale factor
changes.

BUG=1116921
TEST=see bug

Change-Id: Iea87c23e9ea0e6b5934ee568f668388dde489ed6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2405645Reviewed-by: Bo <boliu@chromium.org>
Commit-Queue: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#806628}

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

@@ -2089,10 +2089,16 @@ public class AwContents implements SmartClipProvider {
         return mSettings.supportsMultiTouchZoom();
     }
 
-    public View getZoomControlsForTest() {
+    @VisibleForTesting
+    public View getZoomControlsViewForTest() {
         return mZoomControls.getZoomControlsViewForTest();
     }
 
+    @VisibleForTesting
+    public AwZoomControls getZoomControlsForTest() {
+        return mZoomControls;
+    }
+
     /**
      * @see View#setOverScrollMode(int)
      */
@@ -3551,6 +3557,7 @@ public class AwContents implements SmartClipProvider {
             mContentsClient.getCallbackHelper().postOnScaleChangedScaled(
                     oldPageScaleFactor * dipScale, mPageScaleFactor * dipScale);
         }
+        mZoomControls.updateZoomControls();
     }
 
     private void saveWebArchiveInternal(String path, final Callback<String> callback) {

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

@@ -10,17 +10,31 @@ import android.view.View;
 import android.view.ViewGroup;
 import android.widget.FrameLayout;
 
-class AwZoomControls {
+import androidx.annotation.VisibleForTesting;
 
+// This class is visible purely for tests.
+public class AwZoomControls {
     private AwContents mAwContents;
     // It is advised to use getZoomController() where possible.
     @SuppressWarnings("deprecation")
     private android.widget.ZoomButtonsController mZoomButtonsController;
+    private boolean mCanZoomIn;
+    private boolean mCanZoomOut;
 
     AwZoomControls(AwContents awContents) {
         mAwContents = awContents;
     }
 
+    @VisibleForTesting
+    public boolean canZoomIn() {
+        return mCanZoomIn;
+    }
+
+    @VisibleForTesting
+    public boolean canZoomOut() {
+        return mCanZoomOut;
+    }
+
     @SuppressWarnings("deprecation")
     public void invokeZoomPicker() {
         android.widget.ZoomButtonsController zoomController = getZoomController();
@@ -43,15 +57,15 @@ class AwZoomControls {
         if (zoomController == null) {
             return;
         }
-        boolean canZoomIn = mAwContents.canZoomIn();
-        boolean canZoomOut = mAwContents.canZoomOut();
-        if (!canZoomIn && !canZoomOut) {
+        mCanZoomIn = mAwContents.canZoomIn();
+        mCanZoomOut = mAwContents.canZoomOut();
+        if (!mCanZoomIn && !mCanZoomOut) {
             // Hide the zoom in and out buttons if the page cannot zoom
             zoomController.getZoomControls().setVisibility(View.GONE);
         } else {
             // Set each one individually, as a page may be able to zoom in or out
-            zoomController.setZoomInEnabled(canZoomIn);
-            zoomController.setZoomOutEnabled(canZoomOut);
+            zoomController.setZoomInEnabled(mCanZoomIn);
+            zoomController.setZoomOutEnabled(mCanZoomOut);
         }
     }
 

android_webview/javatests/src/org/chromium/android_webview/test/AwZoomTest.java

@@ -73,8 +73,18 @@ public class AwZoomTest {
         return ThreadUtils.runOnUiThreadBlocking(() -> view.getVisibility());
     }
 
-    private View getZoomControlsOnUiThread() throws Throwable {
-        return ThreadUtils.runOnUiThreadBlocking(() -> mAwContents.getZoomControlsForTest());
+    private View getZoomControlsViewOnUiThread() throws Throwable {
+        return ThreadUtils.runOnUiThreadBlocking(() -> mAwContents.getZoomControlsViewForTest());
+    }
+
+    private boolean canZoomInUsingZoomControls() throws Throwable {
+        return ThreadUtils.runOnUiThreadBlocking(
+                () -> mAwContents.getZoomControlsForTest().canZoomIn());
+    }
+
+    private boolean canZoomOutUsingZoomControls() throws Throwable {
+        return ThreadUtils.runOnUiThreadBlocking(
+                () -> mAwContents.getZoomControlsForTest().canZoomOut());
     }
 
     private void invokeZoomPickerOnUiThread() {
@@ -214,17 +224,43 @@ public class AwZoomTest {
 
         // With DisplayZoomControls set to false, attempts to display zoom
         // controls must be ignored.
-        Assert.assertNull(getZoomControlsOnUiThread());
+        Assert.assertNull(getZoomControlsViewOnUiThread());
         invokeZoomPickerOnUiThread();
-        Assert.assertNull(getZoomControlsOnUiThread());
+        Assert.assertNull(getZoomControlsViewOnUiThread());
 
         webSettings.setDisplayZoomControls(true);
-        Assert.assertNull(getZoomControlsOnUiThread());
+        Assert.assertNull(getZoomControlsViewOnUiThread());
         invokeZoomPickerOnUiThread();
-        View zoomControls = getZoomControlsOnUiThread();
+        View zoomControls = getZoomControlsViewOnUiThread();
         Assert.assertEquals(View.VISIBLE, getVisibilityOnUiThread(zoomControls));
     }
 
+    @Test
+    @SmallTest
+    @Feature({"AndroidWebView"})
+    public void testZoomControlsUiIsUpdatedOnChanges() throws Throwable {
+        AwSettings webSettings = mActivityTestRule.getAwSettingsOnUiThread(mAwContents);
+        webSettings.setDisplayZoomControls(true);
+        webSettings.setBuiltInZoomControls(true);
+        webSettings.setUseWideViewPort(true);
+        Assert.assertFalse(canZoomInUsingZoomControls());
+        Assert.assertFalse(canZoomOutUsingZoomControls());
+        final float pageMinimumScale = 0.5f;
+        mActivityTestRule.loadDataSync(mAwContents, mContentsClient.getOnPageFinishedHelper(),
+                getZoomableHtml(pageMinimumScale), "text/html", false);
+        waitForScaleToBecome(pageMinimumScale);
+        Assert.assertTrue(canZoomInUsingZoomControls());
+        Assert.assertFalse(canZoomOutUsingZoomControls());
+
+        zoomInOnUiThreadAndWait();
+        Assert.assertTrue(canZoomInUsingZoomControls());
+        Assert.assertTrue(canZoomOutUsingZoomControls());
+
+        zoomOutOnUiThreadAndWait();
+        Assert.assertTrue(canZoomInUsingZoomControls());
+        Assert.assertFalse(canZoomOutUsingZoomControls());
+    }
+
     @Test
     @SmallTest
     @Feature({"AndroidWebView"})
@@ -239,9 +275,9 @@ public class AwZoomTest {
         Assert.assertTrue(webSettings.supportZoom());
         webSettings.setBuiltInZoomControls(true);
         webSettings.setDisplayZoomControls(true);
-        Assert.assertNull(getZoomControlsOnUiThread());
+        Assert.assertNull(getZoomControlsViewOnUiThread());
         invokeZoomPickerOnUiThread();
-        View zoomControls = getZoomControlsOnUiThread();
+        View zoomControls = getZoomControlsViewOnUiThread();
         Assert.assertEquals(View.GONE, getVisibilityOnUiThread(zoomControls));
     }