Introduce "disable-speech-api" content flag and add it to WebView.

content/public/common/content_switches.cc

Index: content/public/common/content_switches.cc
diff --git a/content/public/common/content_switches.cc b/content/public/common/content_switches.cc
index 43c7174f4f2c6b789948167f3819c9159a082de2..e0366a61749974275cfdbc299399f00963c3f5c8 100644
--- a/content/public/common/content_switches.cc
+++ b/content/public/common/content_switches.cc
@@ -239,6 +239,9 @@ const char kDisableSmoothScrolling[]        = "disable-smooth-scrolling";
 // Disables the use of a 3D software rasterizer.
 const char kDisableSoftwareRasterizer[]     = "disable-software-rasterizer";
 
+// Disables the Web Speech API.
+const char kDisableSpeech[]                 = "disable-speech";

[Peter Beverloo, 2015/05/08 11:25:00]

Sorry to bikeshed over this, but what about "disable-speech-api"?

When reading this flag, one would suspect that all speech related functionality
in the browser would stop. However, Chrome supports various other kinds of
speech input - the on-screen keyboard, the omnibox, and so on.

Naming it "disable-speech-api" makes it clear that it's about an API. :-)

[timvolodine, 2015/05/12 17:09:20]

agree, done ;)

+
 // Disables SVG 1.1 DOM.
 const char kDisableSVG1DOM[]                = "disable-svg1dom";