Allow editing of commit message from UI.

This change adds a small edit icon on the top right
corner of the commit message box on the change screen.

Clicking it lets the user edit the commit message and a
new patch set will be created.

Change-Id: I2c4d4a3ba520d4c12ade4bb3b47a55ce7f1b19df

gerrit-common/src/main/java/com/google/gerrit/common/data/ChangeDetail.java

@@ -29,6 +29,7 @@ public class ChangeDetail {
   protected AccountInfoCache accounts;
   protected boolean allowsAnonymous;
   protected boolean canAbandon;
+  protected boolean canEditCommitMessage;
   protected boolean canPublish;
   protected boolean canRebase;
   protected boolean canRestore;
@@ -77,6 +78,14 @@ public class ChangeDetail {
     canAbandon = a;
   }
 
+  public boolean canEditCommitMessage() {
+    return canEditCommitMessage;
+  }
+
+  public void setCanEditCommitMessage(final boolean a) {
+    canEditCommitMessage = a;
+  }
+
   public boolean canPublish() {
     return canPublish;
   }