[History] Fix header shown after clearing browsing data

setPrivacyDisclaimer() shouldn't call setHeaders() if headers are not
set when history query completes. This fix would allow header visibility
to rely on the number of history items being shown.

Bug: 790921
Change-Id: Ieb65661490fab08fa65507205f5f32bc23b883c4
Reviewed-on: https://chromium-review.googlesource.com/807207
Commit-Queue: Becky Zhou <huayinz@chromium.org>
Reviewed-by: Theresa <twellington@chromium.org>
Cr-Commit-Position: refs/heads/master@{#521541}

chrome/android/java/src/org/chromium/chrome/browser/history/HistoryAdapter.java

@@ -52,7 +52,7 @@ public class HistoryAdapter extends DateDividedAdapter implements BrowsingHistor
 
     private boolean mHasOtherFormsOfBrowsingData;
     private boolean mIsDestroyed;
-    private boolean mIsInitialized;
+    private boolean mAreHeadersInitialized;
     private boolean mIsLoadingItems;
     private boolean mIsSearching;
     private boolean mHasMorePotentialItems;
@@ -84,7 +84,7 @@ public class HistoryAdapter extends DateDividedAdapter implements BrowsingHistor
      * Initializes the HistoryAdapter and loads the first set of browsing history items.
      */
     public void initialize() {
-        mIsInitialized = false;
+        mAreHeadersInitialized = false;
         mIsLoadingItems = true;
         mClearOnNextQueryComplete = true;
         mHistoryProvider.queryHistory(mQueryText);
@@ -224,9 +224,9 @@ public class HistoryAdapter extends DateDividedAdapter implements BrowsingHistor
             mClearOnNextQueryComplete = false;
         }
 
-        if (!mIsInitialized) {
-            if (items.size() > 0 && !mIsSearching) setHeaders();
-            mIsInitialized = true;
+        if (!mAreHeadersInitialized && items.size() > 0 && !mIsSearching) {
+            setHeaders();
+            mAreHeadersInitialized = true;
         }
 
         removeFooter();
@@ -337,7 +337,7 @@ public class HistoryAdapter extends DateDividedAdapter implements BrowsingHistor
         // Prevent from refreshing the recycler view if header visibility is not changed.
         if (mPrivacyDisclaimersVisible == shouldShowPrivacyDisclaimers) return;
         mPrivacyDisclaimersVisible = shouldShowPrivacyDisclaimers;
-        if (mIsInitialized) setHeaders();
+        if (mAreHeadersInitialized) setHeaders();
     }
 
     private void updateClearBrowsingDataButtonVisibility() {
@@ -349,7 +349,7 @@ public class HistoryAdapter extends DateDividedAdapter implements BrowsingHistor
         if (mClearBrowsingDataButtonVisible == shouldShowButton) return;
         mClearBrowsingDataButtonVisible = shouldShowButton;
         mPrivacyDisclaimerBottomSpace.setVisibility(shouldShowButton ? View.GONE : View.VISIBLE);
-        if (mIsInitialized) setHeaders();
+        if (mAreHeadersInitialized) setHeaders();
     }
 
     @VisibleForTesting