Add a dropdown to control email notifications on user preference page

Add a dropdown 'Email Notifications' in the user preferences to allow
users to control their email notifications.

On selecting 'Disabled' user will not receive any email notifications
from Gerrit.

Remove the checkbox 'CC Me On Comments I write' and add it to the new
dropdown. Functionality remains the same as the original checkbox.

Options in the dropdown are:

1. Enabled
2. CC On Own Comments
3. Disabled

Feature: Issue 989
Change-Id: If40d0d34f39415d5c64ccaa5803fc6321bddd322

gerrit-reviewdb/src/main/java/com/google/gerrit/reviewdb/client/AccountGeneralPreferences.java

@@ -76,6 +76,12 @@ public final class AccountGeneralPreferences {
     UNIFIED_DIFF
   }
 
+  public static enum EmailStrategy {
+    ENABLED,
+    CC_ON_OWN_COMMENTS,
+    DISABLED
+  }
+
   public static enum TimeFormat {
     /** 12-hour clock: 1:15 am, 2:13 pm */
     HHMM_12("h:mm a"),
@@ -120,9 +126,7 @@ public final class AccountGeneralPreferences {
   @Column(id = 6, length = 20, notNull = false)
   protected String downloadCommand;
 
-  /** If true we CC the user on their own changes. */
-  @Column(id = 7)
-  protected boolean copySelfOnEmail;
+  // DELETED: id = 7 (copySelfOnEmail)
 
   @Column(id = 8, length = 10, notNull = false)
   protected String dateFormat;
@@ -155,6 +159,9 @@ public final class AccountGeneralPreferences {
   @Column(id = 19)
   protected boolean muteCommonPathPrefixes;
 
+  @Column(id = 20, length = 30, notNull = false)
+  protected String emailStrategy;
+
   public AccountGeneralPreferences() {
   }
 
@@ -242,14 +249,6 @@ public final class AccountGeneralPreferences {
     }
   }
 
-  public boolean isCopySelfOnEmails() {
-    return copySelfOnEmail;
-  }
-
-  public void setCopySelfOnEmails(boolean includeSelfOnEmail) {
-    copySelfOnEmail = includeSelfOnEmail;
-  }
-
   public boolean isShowInfoInReviewCategory() {
     return getReviewCategoryStrategy() != ReviewCategoryStrategy.NONE;
   }
@@ -307,6 +306,17 @@ public final class AccountGeneralPreferences {
     this.diffView = diffView.name();
   }
 
+  public EmailStrategy getEmailStrategy() {
+    if (emailStrategy == null) {
+      return EmailStrategy.ENABLED;
+    }
+    return EmailStrategy.valueOf(emailStrategy);
+  }
+
+  public void setEmailStrategy(EmailStrategy strategy) {
+    this.emailStrategy = strategy.name();
+  }
+
   public boolean isSizeBarInChangeTable() {
     return sizeBarInChangeTable;
   }
@@ -336,7 +346,6 @@ public final class AccountGeneralPreferences {
     maximumPageSize = DEFAULT_PAGESIZE;
     showSiteHeader = true;
     useFlashClipboard = true;
-    copySelfOnEmail = false;
     reviewCategoryStrategy = null;
     downloadUrl = null;
     downloadCommand = null;
@@ -347,5 +356,6 @@ public final class AccountGeneralPreferences {
     sizeBarInChangeTable = true;
     legacycidInChangeTable = false;
     muteCommonPathPrefixes = true;
+    emailStrategy = null;
   }
 }