Add chrome side webusb permission UI code

chrome/browser/ui/chrome_bubble_manager.cc

Index: chrome/browser/ui/chrome_bubble_manager.cc
diff --git a/chrome/browser/ui/chrome_bubble_manager.cc b/chrome/browser/ui/chrome_bubble_manager.cc
index 33890dcaac7b05f5ec654697313cbff70c47e6ef..82331713383a7e5e82f56b40450d4a5521037c74 100644
--- a/chrome/browser/ui/chrome_bubble_manager.cc
+++ b/chrome/browser/ui/chrome_bubble_manager.cc
@@ -31,6 +31,7 @@ enum BubbleType {
 
   // Permissions-related bubbles:
   BUBBLE_TYPE_PERMISSION = 30,  // Displays a permission request to the user.
+  BUBBLE_TYPE_CHOOSER_PERMISSION = 31,  // For chooser permissions.
 
   // Upper boundary for metrics.
   BUBBLE_TYPE_MAX,
@@ -50,6 +51,8 @@ static int GetBubbleId(BubbleReference bubble) {
     bubble_type = BUBBLE_TYPE_TRANSLATE;
   else if (bubble->GetName().compare("PermissionBubble") == 0)
     bubble_type = BUBBLE_TYPE_PERMISSION;
+  else if (bubble->GetName().compare("ChooserBubble") == 0)

[sky, 2015/12/10 00:32:47]

I'm not familiar with this code. Where are the raw strings coming from?

[juncai, 2015/12/10 00:38:38]

https://codereview.chromium.org/1408193003/diff/590001/chrome/browser/ui/webs...
So for the chooser permission bubble, it overrides BubbleDelegate's
std::string GetName(), it can help collecting metrics.

[sky, 2015/12/10 00:59:15]

Problem with strings is it's easy to change the string and not realize you have
a dependency like this. Can't the bubble return the type?

[juncai, 2015/12/10 01:06:54]

Quoting from email from hcarmona@:
"The reason we use a string to identify the bubble, then convert to an enum is
because the enums are specific to the desktop version of chrome, but we want to
keep the bubble manager independent enough to also work on android and iOS in
the future."

+    bubble_type = BUBBLE_TYPE_CHOOSER_PERMISSION;
 
   DCHECK_NE(bubble_type, BUBBLE_TYPE_UNKNOWN);
   DCHECK_NE(bubble_type, BUBBLE_TYPE_MAX);