Switch AccessibilityMode to be a bitmap

content/common/view_message_enums.h

Index: content/common/view_message_enums.h
diff --git a/content/common/view_message_enums.h b/content/common/view_message_enums.h
index 59a6da11b0aed6f04f35803b5ecde6422763356d..a91e41aa808df7707a0b4460be88a10ef13c5f57 100644
--- a/content/common/view_message_enums.h
+++ b/content/common/view_message_enums.h
@@ -53,19 +53,18 @@ struct ViewMsg_Navigate_Type {
   };
 };
 
-enum AccessibilityMode {
-  // WebKit accessibility is off and no accessibility information is
-  // sent from the renderer to the browser process.
-  AccessibilityModeOff,

[David Tseng, 2014/01/23 18:44:19]

Let's keep an off defined in this enum as 0.

[aboxhall, 2014/01/27 18:03:15]

I added a separate constants enum as discussed.

+enum AccessibilityModeFlag {
+  // WebKit accessibility is on and accessibility information is sent from the

[David Tseng, 2014/01/23 18:44:19]

Blink

[aboxhall, 2014/01/27 18:03:15]

Done.

+  // renderer to the browser process.
+  AccessibilityModeFlagRenderer = 1 << 0,

[David Tseng, 2014/01/23 18:44:19]

Isn't this bit implied for all (except off)? Why do we need this state?

[aboxhall, 2014/01/27 18:03:15]

I just realised I totally misunderstood this comment earlier :)

I agree it's not completely necessary, however it makes things like toggling
accessibility in
https://codereview.chromium.org/145283003/diff/60001/content/browser/accessib...
more straightforward. I thought about renaming it to something like
AccessibilityModeFlagEnabled, but on reflection I think this name is more
accurate. You can, after all, have an accessibility mode which doesn't have this
flag on, but maintains the state for the other flags for when it gets turned
back on.

+
+  // Platform APIs are called for all accessibility updates and events.

[David Tseng, 2014/01/23 18:44:19]

How about:
Accessibility updates are processed to create platform trees and events are
passed to platform APIs in the browser.

[aboxhall, 2014/01/27 18:03:15]

Done.

+  AccessibilityModeFlagPlatform = 1 << 1,
 
   // WebKit accessibility is on, but only limited information about
   // editable text nodes is sent to the browser process. Useful for
   // implementing limited UIA on tablets.
-  AccessibilityModeEditableTextOnly,
-
-  // WebKit accessibility is on, and the full accessibility tree is synced
-  // to the browser process. Useful for screen readers and magnifiers.
-  AccessibilityModeComplete,
+  AccessibilityModeFlagEditableTextOnly = 1 << 2,
 };
 
 #endif  // CONTENT_COMMON_VIEW_MESSAGES_ENUMS_H_