Add deprecation warnings for permission API usage from iframes

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

Index: third_party/WebKit/Source/core/frame/Deprecation.cpp
diff --git a/third_party/WebKit/Source/core/frame/Deprecation.cpp b/third_party/WebKit/Source/core/frame/Deprecation.cpp
index 348a1e23f61178b7fbf1ed8ec6ba4f67c7c417e2..b632bb5de39b73c3da5e34fbe0c99380ec77bdcd 100644
--- a/third_party/WebKit/Source/core/frame/Deprecation.cpp
+++ b/third_party/WebKit/Source/core/frame/Deprecation.cpp
@@ -70,6 +70,15 @@ String replacedWillBeRemoved(const char* feature,
       feature, milestoneString(milestone), replacement, details);
 }
 
+String iframePermissionsWarning(const char* function, Milestone milestone) {
+ return String::Format(
+      "%s usage in cross-origin iframes is deprecated and will be disabled in "
+      "%s. To continue to use this feature, it must be enabled by the "
+      "embedding document using Feature Policy. See https://goo.gl/EuHzyv for "
+      "more details.",
+      function, milestoneString(milestone));
+}
+
 }  // anonymous namespace
 
 namespace blink {
@@ -449,6 +458,14 @@ String Deprecation::DeprecationMessage(WebFeature feature) {
           "is deprecated, and is planned to be removed in %s. Please refer to "
           "https://goo.gl/EGXzpw for possible migration paths.",
           milestoneString(M65));
+    case WebFeature::kEncryptedMediaDisabledIframe:
+      return iframePermissionsWarning("requestMediaKeySystemAccess", M62);

[iclelland, 2017/06/22 15:12:48]

Should the interfaces in these messages be qualified with the object they apply
to? (I see that in a lot of the other deprecation warnings) --
"Geolocation.getCurrentPosition", for instance, rather than just
"getCurrentPosition"

[raymes, 2017/07/05 01:04:25]

Yeah I thought about that. Some things don't seem to though - e.g. the
InsecureOrigin messages which just use the function name. I'm happy to change if
it it's a better approach but I was just following the insecure origin example.
It also just felt easier to read without the fully qualified names and just as
easy to find out what it references.

[iclelland, 2017/07/05 04:41:22]

Sounds good as long as there's no ambiguity there. (getUserMedia can refer to
two different APIs -- navigator and navigator.mediaDevices -- but as long as
they're controlled identically, by the same permissions, I think this is still
okay)

+    case WebFeature::kGeolocationDisabledIframe:
+      return iframePermissionsWarning("getCurrentPosition and watchPosition", M62);
+    case WebFeature::kGetUserMediaDisabledIframe:
+      return iframePermissionsWarning("getUserMedia", M62);
+    case WebFeature::kRequestMIDIAccessDisabledIframe:
+      return iframePermissionsWarning("requestMIDIAccess", M62);
 
     // Features that aren't deprecated don't have a deprecation message.
     default: