Instrument NavigatorDeviceMemory with web IDL bindings for identifiability study.

This reverts the manual instrumentation done in:

https://chromium-review.googlesource.com/c/chromium/src/+/2186997

In favor of bindings-based instrumentation introduced in:

https://chromium-review.googlesource.com/c/chromium/src/+/2245048

Bug: 973801
Change-Id: I0b562c6326689bd084f8a217aa805fa3495fae89
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2267421Reviewed-by: Asanka Herath <asanka@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Commit-Queue: Dylan Cutler <dylancutler@google.com>
Cr-Commit-Position: refs/heads/master@{#784114}

third_party/blink/renderer/core/frame/navigator.cc

@@ -39,9 +39,8 @@
 namespace blink {
 
 Navigator::Navigator(LocalFrame* frame)
-    : ExecutionContextClient(frame),
-      NavigatorDeviceMemory(frame ? frame->GetDocument() : nullptr),
-      NavigatorLanguage(frame ? frame->DomWindow() : nullptr) {}
+    : NavigatorLanguage(frame ? frame->DomWindow() : nullptr),
+      ExecutionContextClient(frame) {}
 
 String Navigator::productSub() const {
   return "20030107";
@@ -120,7 +119,6 @@ void Navigator::Trace(Visitor* visitor) const {
   NavigatorLanguage::Trace(visitor);
   ExecutionContextClient::Trace(visitor);
   Supplementable<Navigator>::Trace(visitor);
-  NavigatorDeviceMemory::Trace(visitor);
 }
 
 ExecutionContext* Navigator::GetUAExecutionContext() const {

third_party/blink/renderer/core/frame/navigator.h

@@ -39,13 +39,13 @@ namespace blink {
 class LocalFrame;
 
 class CORE_EXPORT Navigator final : public ScriptWrappable,
-                                    public ExecutionContextClient,
                                     public NavigatorConcurrentHardware,
                                     public NavigatorDeviceMemory,
                                     public NavigatorID,
                                     public NavigatorLanguage,
                                     public NavigatorOnLine,
                                     public NavigatorUA,
+                                    public ExecutionContextClient,
                                     public Supplementable<Navigator> {
   DEFINE_WRAPPERTYPEINFO();
   USING_GARBAGE_COLLECTED_MIXIN(Navigator);

third_party/blink/renderer/core/frame/navigator_device_memory.cc

@@ -13,25 +13,8 @@
 
 namespace blink {
 
-NavigatorDeviceMemory::NavigatorDeviceMemory(Document* document)
-    : document_(document) {}
-
 float NavigatorDeviceMemory::deviceMemory() const {
-  float result = ApproximatedDeviceMemory::GetApproximatedDeviceMemory();
-  if (document_) {
-    IdentifiabilityMetricBuilder(
-        base::UkmSourceId::FromInt64(document_->UkmSourceID()))
-        .Set(IdentifiableSurface::FromTypeAndInput(
-                IdentifiableSurface::Type::kWebFeature,
-                static_cast<uint64_t>(WebFeature::kNavigatorDeviceMemory)),
-            IdentifiabilityDigestHelper(result))
-        .Record(document_->UkmRecorder());
-  }
-  return result;
-}
-
-void NavigatorDeviceMemory::Trace(Visitor* visitor) const {
-  visitor->Trace(document_);
+  return ApproximatedDeviceMemory::GetApproximatedDeviceMemory();
 }
 
 }  // namespace blink

third_party/blink/renderer/core/frame/navigator_device_memory.h

@@ -6,19 +6,12 @@
 #define THIRD_PARTY_BLINK_RENDERER_CORE_FRAME_NAVIGATOR_DEVICE_MEMORY_H_
 
 #include "third_party/blink/renderer/core/core_export.h"
-#include "third_party/blink/renderer/core/dom/document.h"
 
 namespace blink {
 
-class CORE_EXPORT NavigatorDeviceMemory : public GarbageCollectedMixin {
+class CORE_EXPORT NavigatorDeviceMemory {
  public:
-  explicit NavigatorDeviceMemory();
-  explicit NavigatorDeviceMemory(Document* document);
   float deviceMemory() const;
-  void Trace(Visitor*) const override;
-
- private:
-  WeakMember<Document> document_;
 };
 
 }  // namespace blink

third_party/blink/renderer/core/frame/navigator_device_memory.idl

@@ -5,6 +5,6 @@
 // https://github.com/w3c/device-memory#the-web-exposed-api
 
 interface mixin NavigatorDeviceMemory {
-    [HighEntropy,MeasureAs=NavigatorDeviceMemory,SecureContext]
+    [HighEntropy=Direct,MeasureAs=NavigatorDeviceMemory,SecureContext]
     readonly attribute float deviceMemory;
 };

third_party/blink/renderer/core/workers/worker_navigator.cc

@@ -40,7 +40,6 @@ WorkerNavigator::WorkerNavigator(const String& user_agent,
                                  const UserAgentMetadata& ua_metadata,
                                  ExecutionContext* execution_context)
     : ExecutionContextClient(execution_context),
-      NavigatorDeviceMemory(nullptr),
       NavigatorLanguage(execution_context),
       user_agent_(user_agent),
       ua_metadata_(ua_metadata) {}
@@ -74,7 +73,6 @@ void WorkerNavigator::Trace(Visitor* visitor) const {
   ExecutionContextClient::Trace(visitor);
   NavigatorLanguage::Trace(visitor);
   Supplementable<WorkerNavigator>::Trace(visitor);
-  NavigatorDeviceMemory::Trace(visitor);
 }
 
 }  // namespace blink