Add a UseCounter for execCommand with INPUT or TEXTAREA element.

third_party/WebKit/Source/core/frame/UseCounter.h

Index: third_party/WebKit/Source/core/frame/UseCounter.h
diff --git a/third_party/WebKit/Source/core/frame/UseCounter.h b/third_party/WebKit/Source/core/frame/UseCounter.h
index 4d2939224ee875d58eb2c433f98f9fceb2dfef4a..5d66eaa11914b1fb2237d1439945e2a7ad816aa9 100644
--- a/third_party/WebKit/Source/core/frame/UseCounter.h
+++ b/third_party/WebKit/Source/core/frame/UseCounter.h
@@ -872,6 +872,8 @@ public:
         SelectionDeleteDromDocument = 1011,
         SelectionDOMString = 1012,
         InputTypeRangeVerticalAppearance = 1013,
+        // The above items are available in M48 branch.
+
         CSSFilterReference = 1014,
         CSSFilterGrayscale = 1015,
         CSSFilterSepia = 1016,
@@ -885,6 +887,7 @@ public:
         CSSFilterDropShadow = 1024,
         BackgroundSyncRegister = 1025,
         BorderImageWithBorderStyleNone = 1026,
+        ExecCommandOnInputOrTextarea = 1027,
 
         // Add new features immediately above this line. Don't change assigned
         // numbers of any item, and don't reuse removed slots.