Add CHANGE_SCREEN_BELOW_COMMIT_INFO_BLOCK extension point

Add an extension point on Gerrit UI to allow users to insert
UI components under the commit info panel

Change-Id: I23343d6c09fdd7d063087d8545c3dff6f3d9eaec
diff --git a/Documentation/dev-plugins.txt b/Documentation/dev-plugins.txt
index 3f1ab93..6c3864c 100644
--- a/Documentation/dev-plugins.txt
+++ b/Documentation/dev-plugins.txt
@@ -1080,6 +1080,10 @@
 Panel will be shown in the header bar on the right side of the pop down
 buttons.
 
+** `GerritUiExtensionPoint.CHANGE_SCREEN_BELOW_COMMIT_INFO_BLOCK`:
++
+Panel will be shown below the commit info block.
+
 ** `GerritUiExtensionPoint.CHANGE_SCREEN_BELOW_CHANGE_INFO_BLOCK`:
 +
 Panel will be shown below the change info block.
diff --git a/gerrit-gwtui-common/src/main/java/com/google/gerrit/client/GerritUiExtensionPoint.java b/gerrit-gwtui-common/src/main/java/com/google/gerrit/client/GerritUiExtensionPoint.java
index 088b6fd..0a339a1 100644
--- a/gerrit-gwtui-common/src/main/java/com/google/gerrit/client/GerritUiExtensionPoint.java
+++ b/gerrit-gwtui-common/src/main/java/com/google/gerrit/client/GerritUiExtensionPoint.java
@@ -21,6 +21,7 @@
   CHANGE_SCREEN_HEADER_RIGHT_OF_POP_DOWNS,
   CHANGE_SCREEN_BELOW_CHANGE_INFO_BLOCK,
   CHANGE_SCREEN_BELOW_RELATED_INFO_BLOCK,
+  CHANGE_SCREEN_BELOW_COMMIT_INFO_BLOCK,
 
   /* MyPasswordScreen */
   PASSWORD_SCREEN_BOTTOM,
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 8da949c..5d281d1 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
@@ -190,6 +190,7 @@
   @UiField Element actionDate;
   @UiField SimplePanel changeExtension;
   @UiField SimplePanel relatedExtension;
+  @UiField SimplePanel commitExtension;
 
   @UiField Actions actions;
   @UiField Labels labels;
@@ -337,6 +338,9 @@
     addExtensionPoint(
         GerritUiExtensionPoint.CHANGE_SCREEN_BELOW_RELATED_INFO_BLOCK,
         relatedExtension, change, rev);
+    addExtensionPoint(
+        GerritUiExtensionPoint.CHANGE_SCREEN_BELOW_COMMIT_INFO_BLOCK,
+        commitExtension, change, rev);
   }
 
   private void addExtensionPoint(GerritUiExtensionPoint extensionPoint,
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 0916c00..a0d5405 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
@@ -351,6 +351,10 @@
       padding-top: 5px;
     }
 
+    .commitExtension {
+      padding-top: 5px;
+    }
+
     .pushCertStatus {
       padding-left: 5px;
     }
@@ -434,6 +438,7 @@
       <tr>
         <td class='{style.commitColumn}'>
           <c:CommitBox ui:field='commit'/>
+          <g:SimplePanel ui:field='commitExtension' styleName='{style.commitExtension}'/>
         </td>
         <td class='{style.infoColumn}'>
           <table id='change_infoTable'>