[Android] Add tab observer methods for page load started/stopped.

BUG=344589

Review URL: https://codereview.chromium.org/839553006

Cr-Commit-Position: refs/heads/master@{#310228}

3 files changed, 52 insertions, 0 deletions

diff --git a/chrome/android/java/src/org/chromium/chrome/browser/EmptyTabObserver.java b/chrome/android/java/src/org/chromium/chrome/browser/EmptyTabObserver.java
index 03ca97d..ffefd35 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/EmptyTabObserver.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/EmptyTabObserver.java
@@ -21,6 +21,15 @@ public class EmptyTabObserver implements TabObserver {
     public void onLoadUrl(Tab tab, String url, int loadType) { }
 
     @Override
+    public void onPageLoadStarted(Tab tab) { }
+
+    @Override
+    public void onPageLoadFinished(Tab tab) { }
+
+    @Override
+    public void onPageLoadFailed(Tab tab, int errorCode) { }
+
+    @Override
     public void onFaviconUpdated(Tab tab) { }
 
     @Override
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/Tab.java b/chrome/android/java/src/org/chromium/chrome/browser/Tab.java
index 7131bec..3daba53 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/Tab.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/Tab.java
@@ -485,6 +485,8 @@ public class Tab implements ViewGroup.OnHierarchyChangeListener,
                 observer.onDidFailLoad(Tab.this, isProvisionalLoad, isMainFrame, errorCode,
                         description, failingUrl);
             }
+
+            if (isMainFrame) didFailPageLoad(errorCode);
         }
 
         @Override
@@ -1240,6 +1242,8 @@ public class Tab implements ViewGroup.OnHierarchyChangeListener,
         }
 
         clearHungRendererState();
+
+        for (TabObserver observer : mObservers) observer.onPageLoadStarted(this);
     }
 
     /**
@@ -1249,6 +1253,16 @@ public class Tab implements ViewGroup.OnHierarchyChangeListener,
         mIsTabStateDirty = true;
         updateTitle();
         updateFullscreenEnabledState();
+
+        for (TabObserver observer : mObservers) observer.onPageLoadFinished(this);
+    }
+
+    /**
+     * Called when a page has failed loading.
+     * @param errorCode The error code causing the page to fail loading.
+     */
+    protected void didFailPageLoad(int errorCode) {
+        for (TabObserver observer : mObservers) observer.onPageLoadFailed(this, errorCode);
     }
 
     /**
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/TabObserver.java b/chrome/android/java/src/org/chromium/chrome/browser/TabObserver.java
index 306984f..1d5ad64 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/TabObserver.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/TabObserver.java
@@ -39,6 +39,35 @@ public interface TabObserver {
     void onLoadUrl(Tab tab, String url, int loadType);
 
     /**
+     * Called when a tab has started to load a page.
+     * <p>
+     * This will occur when the main frame has committed a provisional load, and will also
+     * occur in instances where we need to simulate load progress (i.e. swapping in a not
+     * fully loaded pre-rendered page).
+     * <p>
+     * For visual loading indicators/throbbers, {@link #onLoadStarted(Tab)} and
+     * {@link #onLoadStopped(Tab)} should be used to drive updates.
+     *
+     * @param tab The notifying {@link Tab}.
+     */
+    void onPageLoadStarted(Tab tab);
+
+    /**
+     * Called when a tab has finished loading a page.
+     *
+     * @param tab The notifying {@link Tab}.
+     */
+    void onPageLoadFinished(Tab tab);
+
+    /**
+     * Called when a tab has failed loading a page.
+     *
+     * @param tab The notifying {@link Tab}.
+     * @param errorCode The error code that causes the page to fail loading.
+     */
+    void onPageLoadFailed(Tab tab, int errorCode);
+
+    /**
      * Called when the favicon of a {@link Tab} has been updated.
      * @param tab The notifying {@link Tab}.
      */