Use polling to check focused node instead of sleep.

BUG=477632

Review URL: https://codereview.chromium.org/1143443002

Cr-Commit-Position: refs/heads/master@{#329713}

content/public/android/javatests/src/org/chromium/content/browser/input/ImeTest.java

@@ -331,7 +331,16 @@ public class ImeTest extends ContentShellTestBase {
         assertWaitForKeyboardStatus(false);
         DOMUtils.focusNode(mWebContents, "textarea");
         assertWaitForKeyboardStatus(true);
-        Thread.sleep(50);
+        assertTrue(CriteriaHelper.pollForCriteria(new Criteria() {
+            @Override
+            public boolean isSatisfied() {
+                try {
+                    return "textarea".equals(DOMUtils.getFocusedNode(mWebContents));
+                } catch (Exception e) {
+                    return false;
+                }
+            }
+        }));
 
         mConnection = (TestAdapterInputConnection) getAdapterInputConnection();
         waitAndVerifyEditableCallback(mConnection.mImeUpdateQueue, 0, "", 0, 0, -1, -1);
@@ -623,6 +632,16 @@ public class ImeTest extends ContentShellTestBase {
         assertWaitForKeyboardStatus(false);
         DOMUtils.focusNode(mWebContents, "textarea");
         assertWaitForKeyboardStatus(true);
+        assertTrue(CriteriaHelper.pollForCriteria(new Criteria() {
+            @Override
+            public boolean isSatisfied() {
+                try {
+                    return "textarea".equals(DOMUtils.getFocusedNode(mWebContents));
+                } catch (Exception e) {
+                    return false;
+                }
+            }
+        }));
 
         mConnection = (TestAdapterInputConnection) getAdapterInputConnection();
         waitAndVerifyEditableCallback(mConnection.mImeUpdateQueue, 0, "", 0, 0, -1, -1);

content/public/test/android/javatests/src/org/chromium/content/browser/test/util/DOMUtils.java

@@ -152,6 +152,27 @@ public class DOMUtils {
         JavaScriptUtils.executeJavaScriptAndWaitForResult(webContents, sb.toString());
     }
 
+    /**
+     * Get the id of the currently focused node.
+     */
+    public static String getFocusedNode(WebContents webContents)
+            throws InterruptedException, TimeoutException {
+        StringBuilder sb = new StringBuilder();
+        sb.append("(function() {");
+        sb.append("  var node = document.activeElement;");
+        sb.append("  if (!node) return null;");
+        sb.append("  return node.id;");
+        sb.append("})();");
+
+        String id = JavaScriptUtils.executeJavaScriptAndWaitForResult(webContents, sb.toString());
+
+        // String results from JavaScript includes surrounding quotes.  Remove them.
+        if (id != null && id.length() >= 2 && id.charAt(0) == '"') {
+            id = id.substring(1, id.length() - 1);
+        }
+        return id;
+    }
+
     /**
      * Click a DOM node by its id.
      */