Update share and home buttons to disable/enable when url changes instead of when page loads

Bug: 904976
Change-Id: Icfe720a610e4eac8ceb58cbad3c2027cab1f964c
Reviewed-on: https://chromium-review.googlesource.com/c/1368660Reviewed-by: Theresa <twellington@chromium.org>
Commit-Queue: Pedro Amaral <amaralp@chromium.org>
Cr-Commit-Position: refs/heads/master@{#617283}

chrome/android/java/src/org/chromium/chrome/browser/toolbar/HomeButton.java

@@ -91,19 +91,18 @@ public class HomeButton extends ChromeImageButton implements ThemeColorObserver,
             @Override
             public void onObservingDifferentTab(Tab tab) {
                 if (tab == null) return;
-                setEnabled(shouldEnableHome(tab));
+                setEnabled(shouldEnableHome(tab.getUrl()));
             }
 
             @Override
-            public void onPageLoadFinished(Tab tab, String url) {
-                if (tab == null) return;
-                setEnabled(shouldEnableHome(tab));
+            public void onUpdateUrl(Tab tab, String url) {
+                setEnabled(shouldEnableHome(url));
             }
         };
     }
 
-    private static boolean shouldEnableHome(Tab tab) {
+    private static boolean shouldEnableHome(String url) {
         if (!FeatureUtilities.isBottomToolbarEnabled()) return true;
-        return !NewTabPage.isNTPUrl(tab.getUrl());
+        return !NewTabPage.isNTPUrl(url);
     }
 }

chrome/android/java/src/org/chromium/chrome/browser/toolbar/bottom/ShareButton.java

@@ -45,7 +45,7 @@ class ShareButton extends ChromeImageButton implements ThemeColorObserver {
             }
 
             @Override
-            public void onPageLoadFinished(Tab tab, String url) {
+            public void onUpdateUrl(Tab tab, String url) {
                 if (tab == null) return;
                 setEnabled(shouldEnableShare(tab));
             }