Merge changes from topic 'bot-comments-ui-gh16'

* changes:
  Hide "HideBotComments" if no bot comment is present in the history tab
  Add show / hide bot comments button to ChangeScreen
diff --git a/gerrit-gwtui-common/src/main/java/com/google/gerrit/client/info/ChangeInfo.java b/gerrit-gwtui-common/src/main/java/com/google/gerrit/client/info/ChangeInfo.java
index 9eea93e..b29a3de 100644
--- a/gerrit-gwtui-common/src/main/java/com/google/gerrit/client/info/ChangeInfo.java
+++ b/gerrit-gwtui-common/src/main/java/com/google/gerrit/client/info/ChangeInfo.java
@@ -458,7 +458,8 @@
     public final native AccountInfo author() /*-{ return this.author; }-*/;
     public final native String message() /*-{ return this.message; }-*/;
     public final native int _revisionNumber() /*-{ return this._revision_number || 0; }-*/;
-    private native String dateRaw() /*-{ return this.date; }-*/;
+    public final native String tag() /*-{ return this.tag; }-*/;
+    private final native String dateRaw() /*-{ return this.date; }-*/;
 
     public final Timestamp date() {
       return JavaSqlTimestamp_JsonSerializer.parseTimestamp(dateRaw());
diff --git a/gerrit-gwtui/src/main/java/com/google/gerrit/client/change/ChangeScreen.java b/gerrit-gwtui/src/main/java/com/google/gerrit/client/change/ChangeScreen.java
index 55d22a9..0ab989f 100644
--- a/gerrit-gwtui/src/main/java/com/google/gerrit/client/change/ChangeScreen.java
+++ b/gerrit-gwtui/src/main/java/com/google/gerrit/client/change/ChangeScreen.java
@@ -225,6 +225,8 @@
   @UiField Button renameFile;
   @UiField Button expandAll;
   @UiField Button collapseAll;
+  @UiField Button hideTaggedComments;
+  @UiField Button showTaggedComments;
   @UiField QuickApprove quickApprove;
 
   private ReplyAction replyAction;
@@ -300,6 +302,13 @@
                       .defaultBaseForMerges().getBase();
                 }
                 loadConfigInfo(info, base);
+                JsArray<MessageInfo> mAr = info.messages();
+                for (int i = 0; i < mAr.length(); i++) {
+                  if (mAr.get(i).tag() != null) {
+                    hideTaggedComments.setVisible(true);
+                    break;
+                  }
+                }
               }
             });
             group.done();
@@ -908,6 +917,30 @@
     }
   }
 
+  @UiHandler("showTaggedComments")
+  void onShowTaggedComments(@SuppressWarnings("unused") ClickEvent e) {
+    showTaggedComments.setVisible(false);
+    hideTaggedComments.setVisible(true);
+    int n = history.getWidgetCount();
+    for (int i = 0; i < n; i++) {
+      Message m = ((Message) history.getWidget(i));
+      m.setVisible(true);
+    }
+  }
+
+  @UiHandler("hideTaggedComments")
+  void onHideTaggedComments(@SuppressWarnings("unused") ClickEvent e) {
+    hideTaggedComments.setVisible(false);
+    showTaggedComments.setVisible(true);
+    int n = history.getWidgetCount();
+    for (int i = 0; i < n; i++) {
+      Message m = ((Message) history.getWidget(i));
+      if (m.getMessageInfo().tag() != null) {
+        m.setVisible(false);
+      }
+    }
+  }
+
   @UiHandler("expandAll")
   void onExpandAll(@SuppressWarnings("unused") ClickEvent e) {
     int n = history.getWidgetCount();
diff --git a/gerrit-gwtui/src/main/java/com/google/gerrit/client/change/ChangeScreen.ui.xml b/gerrit-gwtui/src/main/java/com/google/gerrit/client/change/ChangeScreen.ui.xml
index 7790044..fe48eb9 100644
--- a/gerrit-gwtui/src/main/java/com/google/gerrit/client/change/ChangeScreen.ui.xml
+++ b/gerrit-gwtui/src/main/java/com/google/gerrit/client/change/ChangeScreen.ui.xml
@@ -606,6 +606,20 @@
           <ui:attribute name='title'/>
           <div><ui:msg>Collapse All</ui:msg></div>
         </g:Button>
+        <g:Button ui:field='hideTaggedComments'
+            styleName=''
+            visible='false'
+            title='Hide tagged comments'>
+          <ui:attribute name='title'/>
+          <div><ui:msg>Hide tagged comments</ui:msg></div>
+        </g:Button>
+        <g:Button ui:field='showTaggedComments'
+            styleName=''
+            visible='false'
+            title='Show tagged comments'>
+          <ui:attribute name='title'/>
+          <div><ui:msg>Show tagged comments</ui:msg></div>
+        </g:Button>
         <g:SimplePanel ui:field='historyExtensionRight' styleName='{style.historyExtension}'/>
       </div>
     </div>