Remove --enable-input-mode-attribute flag

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 c42a501e1a42245422f943c96866a1787399a1cd..42620ebe2cb4094b401b18a0ebc204d17c48a46b 100644
--- a/content/public/common/content_switches.cc
+++ b/content/public/common/content_switches.cc
@@ -489,9 +489,6 @@ extern const char kEnableHTMLImports[]      = "enable-html-imports";
 // Enables support for inband text tracks in media content.
 const char kEnableInbandTextTracks[]        = "enable-inband-text-tracks";
 
-// Enable inputmode attribute of HTML input or text element.
-extern const char kEnableInputModeAttribute[] = "enable-input-mode-attribute";
-
 // Force logging to be enabled.  Logging is disabled by default in release
 // builds.
 const char kEnableLogging[]                 = "enable-logging";