Add deprecation message for kDataUriHasOctothorpe

We are aiming to deprecate this feature in M67. This warning may have
some false positives (as it is legal to use '#' as a fragment
identifier), but I have yet to find a case in the wild of someone
actually doing that.

Intent: https://groups.google.com/a/chromium.org/d/msg/blink-dev/_g_HnAHkMPo/1DrejG5mAgAJ

Bug: 123004
Change-Id: Ibace7288ddb6a814f51faec85c47a49b0d69a273
Reviewed-on: https://chromium-review.googlesource.com/888762
Commit-Queue: Stephen McGruer <smcgruer@chromium.org>
Reviewed-by: Rick Byers <rbyers@chromium.org>
Reviewed-by: David Benjamin <davidben@chromium.org>
Cr-Commit-Position: refs/heads/master@{#533298}

third_party/WebKit/Source/core/frame/Deprecation.cpp

@@ -608,6 +608,12 @@ DeprecationInfo GetDeprecationInfo(WebFeature feature) {
       return {"ChromeLoadTimesWasAlternateProtocolAvailable", Unknown,
               chromeLoadTimesNextHopProtocol};
 
+    case WebFeature::kDataUriHasOctothorpe:
+      return {"DataUriHasOctothorpe", M67,
+              replacedWillBeRemoved(
+                  "Using unescaped '#' characters in a data URI body", "'%23'",
+                  M67, "5656049583390720")};
+
     case WebFeature::kThreeValuedPositionBasicShape:
     case WebFeature::kThreeValuedPositionGradient:
     case WebFeature::kThreeValuedPositionObjectPosition:

third_party/WebKit/Source/core/loader/FrameFetchContext.cpp

@@ -43,7 +43,6 @@
 #include "core/frame/LocalFrameClient.h"
 #include "core/frame/LocalFrameView.h"
 #include "core/frame/Settings.h"
-#include "core/frame/UseCounter.h"
 #include "core/html/HTMLFrameOwnerElement.h"
 #include "core/html/imports/HTMLImportsController.h"
 #include "core/inspector/ConsoleMessage.h"
@@ -1248,7 +1247,7 @@ void FrameFetchContext::Trace(blink::Visitor* visitor) {
 }
 
 void FrameFetchContext::RecordDataUriWithOctothorpe() {
-  UseCounter::Count(GetFrame(), WebFeature::kDataUriHasOctothorpe);
+  CountDeprecation(WebFeature::kDataUriHasOctothorpe);
 }
 
 ResourceLoadPriority FrameFetchContext::ModifyPriorityForExperiments(