heap: Various fixes for compiling with Oilpan library

- Fix cppgc traits for TraceWrapperV8Reference
- Fix ThreadState compilation
- Fix String resolution

Bug: 1056170
Change-Id: I95f6ce324b632465e936a0b6d00aab082e28507c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2616199Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#841415}

third_party/blink/renderer/platform/BUILD.gn

@@ -1658,6 +1658,7 @@ component("platform") {
     "//third_party/blink/public/common",
     "//third_party/blink/public/strings",
     "//third_party/blink/renderer/platform/wtf",
+    "//third_party/blink/renderer/platform/wtf:buildflags",
     "//third_party/ced",
     "//third_party/emoji-segmenter",
     "//third_party/harfbuzz-ng:hb_scoped_util",

third_party/blink/renderer/platform/bindings/trace_wrapper_v8_reference.h

@@ -11,9 +11,17 @@
 #include "base/macros.h"
 #include "third_party/blink/renderer/platform/heap/unified_heap_marking_visitor.h"
 #include "third_party/blink/renderer/platform/wtf/allocator/allocator.h"
+#include "third_party/blink/renderer/platform/wtf/buildflags.h"
 #include "third_party/blink/renderer/platform/wtf/vector_traits.h"
 #include "v8/include/v8.h"
 
+namespace cppgc {
+
+template <typename T>
+struct TraceTrait;
+
+}  // namespace cppgc
+
 namespace blink {
 
 template <typename T>
@@ -123,13 +131,37 @@ class TraceWrapperV8Reference {
   }
 
   v8::TracedReference<T> handle_;
+
+  friend struct cppgc::TraceTrait<TraceWrapperV8Reference<T>>;
 };
+}  // namespace blink
+
+#if BUILDFLAG(USE_V8_OILPAN)
 
+namespace cppgc {
+template <typename T>
+struct TraceTrait<TraceWrapperV8Reference<T>> {
+  STATIC_ONLY(TraceTrait);
+
+  static cppgc::TraceDescriptor GetTraceDescriptor(
+      const TraceWrapperV8Reference<T>* ref) {
+    return {ref, Trace};
+  }
+
+  static void Trace(Visitor* visitor, const void* self) {
+    visitor->Trace(
+        static_cast<const TraceWrapperV8Reference<T>*>(self)->handle_);
+  }
+};
+}  // namespace cppgc
+
+#else  // !USE_V8_OILPAN
+
+namespace blink {
 template <typename T>
 struct TraceTrait<TraceWrapperV8Reference<T>> {
   STATIC_ONLY(TraceTrait);
 
- public:
   static TraceDescriptor GetTraceDescriptor(
       const TraceWrapperV8Reference<T>* ref) {
     return {ref, TraceTrait<TraceWrapperV8Reference<T>>::Trace};
@@ -139,9 +171,10 @@ struct TraceTrait<TraceWrapperV8Reference<T>> {
     visitor->Trace(*static_cast<const TraceWrapperV8Reference<T>*>(ref));
   }
 };
-
 }  // namespace blink
 
+#endif  // !USE_V8_OILPAN
+
 namespace WTF {
 
 template <typename T>

third_party/blink/renderer/platform/heap/v8_wrapper/thread_state.cc

@@ -34,9 +34,9 @@ void ThreadState::DetachCurrentThread() {
 }
 
 ThreadState::ThreadState(v8::CppHeap& cpp_heap)
-    : cpp_heap_(cpp_heap),
-      allocation_handle_(cpp_heap.GetAllocationHandle())
-          thread_id_(CurrentThread()) {}
+    : allocation_handle_(cpp_heap.GetAllocationHandle()),
+      cpp_heap_(cpp_heap),
+      thread_id_(CurrentThread()) {}
 
 ThreadState::~ThreadState() {
   DCHECK(!IsMainThread());

third_party/blink/renderer/platform/heap/v8_wrapper/thread_state.h

@@ -5,6 +5,7 @@
 #ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_HEAP_V8_WRAPPER_THREAD_STATE_H_
 #define THIRD_PARTY_BLINK_RENDERER_PLATFORM_HEAP_V8_WRAPPER_THREAD_STATE_H_
 
+#include "base/compiler_specific.h"
 #include "base/lazy_instance.h"
 #include "third_party/blink/renderer/platform/wtf/allocator/allocator.h"
 #include "third_party/blink/renderer/platform/wtf/thread_specific.h"
@@ -68,6 +69,7 @@ class ThreadState final {
   ALWAYS_INLINE cppgc::AllocationHandle& allocation_handle() const {
     return allocation_handle_;
   }
+  ALWAYS_INLINE v8::CppHeap& cpp_heap() const { return cpp_heap_; }
 
  private:
   // Main-thread ThreadState avoids TLS completely by using a regular global.

third_party/blink/renderer/platform/scheduler/worker/worker_thread.h

@@ -15,6 +15,7 @@
 #include "third_party/blink/public/platform/web_private_ptr.h"
 #include "third_party/blink/renderer/platform/heap/gc_task_runner.h"
 #include "third_party/blink/renderer/platform/scheduler/public/thread.h"
+#include "third_party/blink/renderer/platform/wtf/text/wtf_string.h"
 
 namespace blink {
 class BlinkGCMemoryDumpProvider;