Return void in zoomBy plumbing to match zoomBy public API

BUG=410900

Review URL: https://codereview.chromium.org/881383002

Cr-Commit-Position: refs/heads/master@{#313617}

android_webview/glue/java/src/com/android/webview/chromium/WebViewChromium.java

@@ -1448,12 +1448,15 @@ class WebViewChromium implements WebViewProvider, WebViewProvider.ScrollDelegate
         return mAwContents.zoomOut();
     }
 
+    // TODO(paulmiller) Return void for consistency with AwContents.zoomBy and WebView.zoomBy -
+    // tricky because frameworks WebViewProvider.zoomBy must change simultaneously
     @Override
     public boolean zoomBy(float factor) {
         mFactory.startYourEngines(true);
         // This is an L API and therefore we can enforce stricter threading constraints.
         checkThread();
-        return mAwContents.zoomBy(factor);
+        mAwContents.zoomBy(factor);
+        return true;
     }
 
     @Override

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

@@ -1710,7 +1710,8 @@ public class AwContents implements SmartClipProvider {
         if (!canZoomIn()) {
             return false;
         }
-        return zoomBy(1.25f);
+        zoomBy(1.25f);
+        return true;
     }
 
     /**
@@ -1722,7 +1723,8 @@ public class AwContents implements SmartClipProvider {
         if (!canZoomOut()) {
             return false;
         }
-        return zoomBy(0.8f);
+        zoomBy(0.8f);
+        return true;
     }
 
     /**
@@ -1730,12 +1732,12 @@ public class AwContents implements SmartClipProvider {
      */
     // This method uses the term 'zoom' for legacy reasons, but relates
     // to what chrome calls the 'page scale factor'.
-    public boolean zoomBy(float delta) {
-        if (isDestroyed()) return false;
+    public void zoomBy(float delta) {
+        if (isDestroyed()) return;
         if (delta < 0.01f || delta > 100.0f) {
             throw new IllegalStateException("zoom delta value outside [0.01, 100] range.");
         }
-        return mContentViewCore.pinchByDelta(delta);
+        mContentViewCore.pinchByDelta(delta);
     }
 
     /**

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

@@ -120,12 +120,12 @@ public class AwZoomTest extends AwTestBase {
 
     private void zoomByOnUiThreadAndWait(final float delta) throws Throwable {
         final float previousScale = getPixelScaleOnUiThread(mAwContents);
-        assertTrue(runTestOnUiThreadAndGetResult(new Callable<Boolean>() {
+        ThreadUtils.runOnUiThreadBlocking(new Runnable() {
             @Override
-            public Boolean call() throws Exception {
-                return mAwContents.zoomBy(delta);
+            public void run() {
+                mAwContents.zoomBy(delta);
             }
-        }));
+        });
         // The zoom level is updated asynchronously.
         waitForScaleChange(previousScale);
     }