[Home] Ensure toolbar is visible before expanding sheet

This change forces the toolbar to be shown in cases where it is hidden
and the bottom sheet is opened.

BUG=741320

Change-Id: Iad9ff71e0e71ae15c50f6db02bf194db4d97131b
Reviewed-on: https://chromium-review.googlesource.com/576198Reviewed-by: Theresa <twellington@chromium.org>
Reviewed-by: Ted Choc <tedchoc@chromium.org>
Commit-Queue: Matthew Jones <mdjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#488268}

chrome/android/java/src/org/chromium/chrome/browser/widget/bottomsheet/BottomSheet.java

@@ -59,6 +59,7 @@ import org.chromium.chrome.browser.widget.textbubble.ViewAnchoredTextBubble;
 import org.chromium.content.browser.BrowserStartupController;
 import org.chromium.content.browser.ContentViewCore;
 import org.chromium.content_public.browser.LoadUrlParams;
+import org.chromium.content_public.common.BrowserControlsState;
 import org.chromium.ui.UiUtils;
 
 import java.lang.annotation.Retention;
@@ -523,6 +524,7 @@ public class BottomSheet
         if (!isSheetOpen() && tab != null && !tab.canGoBack() && !isInOverviewMode()
                 && tab.getLaunchType() == TabLaunchType.FROM_CHROME_UI) {
             mBackButtonDismissesChrome = true;
+
             setSheetState(SHEET_STATE_HALF, true);
             return true;
         } else if (isSheetOpen() && !mBackButtonDismissesChrome) {
@@ -674,7 +676,8 @@ public class BottomSheet
     /**
      * @return Whether or not the toolbar Android View is hidden due to being scrolled off-screen.
      */
-    private boolean isToolbarAndroidViewHidden() {
+    @VisibleForTesting
+    public boolean isToolbarAndroidViewHidden() {
         return mFullscreenManager == null || mFullscreenManager.getBottomControlOffset() > 0
                 || mControlContainer.getVisibility() != VISIBLE;
     }
@@ -1030,6 +1033,12 @@ public class BottomSheet
     private void onSheetOpened() {
         if (mIsSheetOpen) return;
 
+        // Make sure the toolbar is visible before expanding the sheet.
+        Tab tab = getActiveTab();
+        if (isToolbarAndroidViewHidden() && tab != null) {
+            tab.updateBrowserControlsState(BrowserControlsState.SHOWN, false);
+        }
+
         mIsSheetOpen = true;
         dismissSelectedText();
         for (BottomSheetObserver o : mObservers) o.onSheetOpened();

chrome/android/javatests/src/org/chromium/chrome/browser/widget/bottomsheet/BottomSheetBackBehaviorTest.java

@@ -168,6 +168,30 @@ public class BottomSheetBackBehaviorTest {
         assertFalse("Chrome should no longer have focus.", mActivity.hasWindowFocus());
     }
 
+    @Test
+    @SmallTest
+    public void testBackButton_backButtonOpensSheetAndShowsToolbar()
+            throws ExecutionException, InterruptedException, TimeoutException {
+        final Tab tab = launchNewTabFromChrome("about:blank");
+
+        assertEquals("Tab should be on about:blank.", "about:blank", tab.getUrl());
+
+        assertEquals("The bottom sheet should be peeking.", BottomSheet.SHEET_STATE_PEEK,
+                mBottomSheet.getSheetState());
+
+        // This also waits for the controls to be hidden.
+        hideBrowserControls(tab);
+
+        // Back button press should open the bottom sheet since backward navigation is not
+        // possible and show the toolbar.
+        pressBackButton();
+        endBottomSheetAnimations();
+
+        waitForShownBrowserControls();
+        assertEquals("The bottom sheet should be at half height.", BottomSheet.SHEET_STATE_HALF,
+                mBottomSheet.getSheetState());
+    }
+
     @Test
     @SmallTest
     public void testBackButton_backWithNavigation()
@@ -260,6 +284,39 @@ public class BottomSheetBackBehaviorTest {
         });
     }
 
+    /**
+     * Wait for the browser controls to be hidden.
+     * @param tab The active tab.
+     */
+    private void hideBrowserControls(final Tab tab) throws ExecutionException {
+        // Hide the browser controls.
+        ThreadUtils.runOnUiThreadBlocking(new Runnable() {
+            @Override
+            public void run() {
+                tab.getActivity().getFullscreenManager().setHideBrowserControlsAndroidView(true);
+            }
+        });
+
+        CriteriaHelper.pollUiThread(new Criteria() {
+            @Override
+            public boolean isSatisfied() {
+                return mBottomSheet.isToolbarAndroidViewHidden();
+            }
+        });
+    }
+
+    /**
+     * Wait for the browser controls to be shown.
+     */
+    private void waitForShownBrowserControls() throws ExecutionException {
+        CriteriaHelper.pollUiThread(new Criteria() {
+            @Override
+            public boolean isSatisfied() {
+                return !mBottomSheet.isToolbarAndroidViewHidden();
+            }
+        });
+    }
+
     /** Notify the activity that the hardware back button was pressed. */
     private void pressBackButton() {
         ThreadUtils.runOnUiThreadBlocking(new Runnable() {