Add 5 experimental accessibility features on Chrome OS.

chrome/common/pref_names.h

Index: chrome/common/pref_names.h
diff --git a/chrome/common/pref_names.h b/chrome/common/pref_names.h
index 21b75d50c97fb2d66b36b98d6964f5c77af17cd3..25a2bb0dbd429257f9d6e9e3c1494ca4463f52c9 100644
--- a/chrome/common/pref_names.h
+++ b/chrome/common/pref_names.h
@@ -215,6 +215,11 @@ extern const char kAccessibilityScreenMagnifierScale[];
 extern const char kAccessibilityVirtualKeyboardEnabled[];
 extern const char kAccessibilityAutoclickEnabled[];
 extern const char kAccessibilityAutoclickDelayMs[];
+extern const char kAccessibilityCaretHighlightEnabled[];
+extern const char kAccessibilityCursorHighlightEnabled[];
+extern const char kAccessibilityFocusHighlightEnabled[];
+extern const char kAccessibilitySelectToSpeakEnabled[];
+extern const char kAccessibilitySwitchAccessEnabled[];

[oshima, 2016/03/11 02:20:55]

does these pref key have to be in chrome/ ? 

pref service is componentized, so they can be in ash unless it has to use
class/API in chrome/.

[dmazzoni, 2016/03/11 15:11:28]

All of these have at least some of their implementation in
chrome/browser/*chromeos* - for example the magnifier does focus tracking,
spoken feedback starts and stops the extension, and so on.

Would it make more sense to move them to /chromeos/chromeos_pref_names? That
makes more sense to me than ash/ - don't we still have a bot that compiles ash
on Windows?

[oshima, 2016/03/14 23:19:52]

Focus tracking seems to depend on content, not chrome, and extension api do not
have to be in chrome/browser. see extensions/browser/api.

I understand that the some of accessibility implementations may need access
chrome/browser, and that's where we need delegate.
I also strongly recommend to stop using chrome/browser interface directly, such
as Profile (use BrowserContext instead), BrowserProcess (pass objects).
Or ui/chromeos/accessibility or components/accessibility, if we can move more
code out from chrome/browser, as chromeos for non UI stuff.

For win_ash, you can just exclude it on Windows. It's does not have
accessibility stuff now, so it's not a regression.

It doesn't have to be in this CL, but this is getting more important for
mustash, and it's better to do this sooner than later. Can you at least file a
bug and add TODO here?

 extern const char kShouldAlwaysShowAccessibilityMenu[];
 extern const char kLabsAdvancedFilesystemEnabled[];
 extern const char kLabsMediaplayerEnabled[];