Lo-Fi snackbar should only be shown for the first q=low response of a page

chrome/android/java/src/org/chromium/chrome/browser/snackbar/LoFiBarPopupController.java

Index: chrome/android/java/src/org/chromium/chrome/browser/snackbar/LoFiBarPopupController.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/snackbar/LoFiBarPopupController.java b/chrome/android/java/src/org/chromium/chrome/browser/snackbar/LoFiBarPopupController.java
index 3afad9752451f1d638b0cd0fe255eaccff8845e7..7b2c0035877ab2ac398231b49693eea2f3042672 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/snackbar/LoFiBarPopupController.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/snackbar/LoFiBarPopupController.java
@@ -11,7 +11,9 @@ import org.chromium.chrome.R;
 import org.chromium.chrome.browser.ChromeSwitches;
 import org.chromium.chrome.browser.net.spdyproxy.DataReductionProxySettings;
 import org.chromium.chrome.browser.preferences.datareduction.DataReductionProxyUma;
+import org.chromium.chrome.browser.tab.EmptyTabObserver;
 import org.chromium.chrome.browser.tab.Tab;
+import org.chromium.chrome.browser.tab.TabObserver;
 
 /**
  * Each time a tab loads with Lo-Fi this controller saves that tab id and title to the stack of
@@ -26,6 +28,7 @@ public class LoFiBarPopupController implements SnackbarManager.SnackbarControlle
     private final Context mContext;
     private final boolean mDisabled;
     private Tab mTab;
+    private boolean mLoFiPopupShownForPageLoad = false;
 
     /**
      * Creates an instance of a {@link LoFiBarPopupController}.
@@ -39,9 +42,50 @@ public class LoFiBarPopupController implements SnackbarManager.SnackbarControlle
     }
 
     /**
+     * Called on new page loads to indicate that a Lo-Fi snackbar has not been shown yet.
+     */
+    public void resetLoFiPopupShownForPageLoad() {
+        mLoFiPopupShownForPageLoad = false;
+    }
+
+    /**
+     * If a Lo-Fi snackbar has not been shown for the current page load, creates a Lo-Fi snackbar
+     * for the given tab and shows it. If the tab is hidden, waits until it is visible to show the
+     * snackbar.
+     *
+     * @param tab The tab to show the snackbar on.
+     */
+    public void maybeCreateLoFiBar(Tab tab) {
+        if (mLoFiPopupShownForPageLoad) return;
+        mLoFiPopupShownForPageLoad = true;
+        if (tab.isHidden()) {
+            TabObserver tabObserver = new EmptyTabObserver() {
+                @Override
+                public void onShown(Tab tab) {
+                    showLoFiBar(tab);
+                    tab.removeObserver(this);
+                }
+
+                @Override
+                public void onHidden(Tab tab) {
+                    dismissLoFiBar();
+                }
+
+                @Override
+                public void onDestroyed(Tab tab) {
+                    dismissLoFiBar();
+                }
+            };
+            tab.addObserver(tabObserver);
+            return;
+        }
+        showLoFiBar(tab);
+    }
+
+    /**
      * @param tab The tab. Saved to reload the page.
      */
-    public void showLoFiBar(Tab tab) {
+    private void showLoFiBar(Tab tab) {
         if (mDisabled) return;
         mTab = tab;
         mSnackbarManager.showSnackbar(Snackbar.make(
@@ -57,7 +101,7 @@ public class LoFiBarPopupController implements SnackbarManager.SnackbarControlle
     /**
      * Dismisses the snackbar.
      */
-    public void dismissLoFiBar() {
+    private void dismissLoFiBar() {
         if (mSnackbarManager.isShowing()) mSnackbarManager.dismissSnackbars(this);
     }