Revert "[oilpan] Move incremental marking behind a build-time flag"

This reverts commit 9966b73a.

Reason for revert: I suspect this caused the compile failure here:
https://ci.chromium.org/buildbot/chromium.webkit/WebKit%20Win%20x64%20Builder%20(dbg)/116281

Original change's description:
> [oilpan] Move incremental marking behind a build-time flag
> 
> Move Oilpan's incremental marking work behind a build-time flag
>   enable_blink_heap_incremental_marking
> 
> Bug: chromium:757440
> Change-Id: Id4adddcf0669dc165935eced90e8caefbb76a094
> Reviewed-on: https://chromium-review.googlesource.com/822492
> Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
> Reviewed-by: Kentaro Hara <haraken@chromium.org>
> Reviewed-by: Dirk Pranke <dpranke@chromium.org>
> Reviewed-by: Jeremy Roman <jbroman@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#524051}

TBR=jbroman@chromium.org,dpranke@chromium.org,haraken@chromium.org,mlippautz@chromium.org

Change-Id: I15da11c96b51ede50f4fb0742d6859117b2d4175
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:757440
Reviewed-on: https://chromium-review.googlesource.com/826699Reviewed-by: Robert Flack <flackr@chromium.org>
Commit-Queue: Robert Flack <flackr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#524055}

third_party/WebKit/Source/platform/BUILD.gn

@@ -1481,7 +1481,6 @@ jumbo_component("platform") {
     "//services/service_manager/public/interfaces:interfaces_blink",
     "//skia",
     "//third_party:jpeg",
-    "//third_party/WebKit/Source/platform/heap",
     "//third_party/WebKit/Source/platform/wtf",
     "//third_party/WebKit/common:blink_common",
     "//third_party/WebKit/common:mojo_platform_bindings_blink",
@@ -1502,6 +1501,7 @@ jumbo_component("platform") {
     "//services/service_manager/public/cpp",
     "//third_party:freetype_harfbuzz",
     "//third_party/WebKit/Source/platform/blob",
+    "//third_party/WebKit/Source/platform/heap",
     "//third_party/WebKit/Source/platform/instrumentation",
     "//third_party/WebKit/Source/platform/loader",
     "//third_party/WebKit/Source/platform/media",
@@ -1912,10 +1912,6 @@ jumbo_source_set("blink_platform_unittests_sources") {
     "//third_party/WebKit/Source:config",
   ]
 
-  public_deps = [
-    "//third_party/WebKit/Source/platform/heap",
-  ]
-
   deps = [
     ":platform",
     ":test_support",

third_party/WebKit/Source/platform/heap/BUILD.gn

@@ -2,29 +2,13 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-import("//build/buildflag_header.gni")
 import("//build/config/jumbo.gni")
 import("//testing/test.gni")
 
-declare_args() {
-  # Enables incremental marking in Oilpan.
-  enable_blink_heap_incremental_marking = false
-}
-
-buildflag_header("blink_heap_incremental_marking") {
-  header = "IncrementalMarking.h"
-
-  header_dir = "blink/platform/heap"
-
-  flags = [
-    "BLINK_HEAP_INCREMENTAL_MARKING=$enable_blink_heap_incremental_marking",
-  ]
-}
-
 jumbo_source_set("heap") {
   # This target is a logical part of the platform and only the platform target
   # should depend on it.
-  visibility = [ "//third_party/WebKit/Source/platform:*" ]
+  visibility = [ "//third_party/WebKit/Source/platform" ]
 
   sources = [
     "BlinkGC.h",
@@ -90,7 +74,6 @@ jumbo_source_set("heap") {
   ]
 
   public_deps = [
-    ":blink_heap_incremental_marking",
     "//third_party/WebKit/public:blink_headers",
   ]
 }

third_party/WebKit/Source/platform/heap/IncrementalMarkingTest.cpp

@@ -5,13 +5,13 @@
 #include "platform/heap/CallbackStack.h"
 #include "platform/heap/GarbageCollected.h"
 #include "platform/heap/Heap.h"
-#include "platform/heap/IncrementalMarking.h"
 #include "platform/heap/Member.h"
 #include "platform/heap/ThreadState.h"
 #include "platform/heap/TraceTraits.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
-#if BUILDFLAG(BLINK_HEAP_INCREMENTAL_MARKING)
+// TODO(mlippautz): Replace with proper build flag.
+#if 0
 
 namespace blink {
 namespace incremental_marking_test {
@@ -214,4 +214,4 @@ TEST(IncrementalMarkingTest, NoWriteBarrierOnMarkedMixinApplication) {
 }  // namespace incremental_marking_test
 }  // namespace blink
 
-#endif  // BUILDFLAG(BLINK_HEAP_INCREMENTAL_MARKING)
+#endif

third_party/WebKit/Source/platform/heap/Member.h

@@ -7,7 +7,6 @@
 
 #include "platform/heap/Heap.h"
 #include "platform/heap/HeapPage.h"
-#include "platform/heap/IncrementalMarking.h"
 #include "platform/wtf/Allocator.h"
 #include "platform/wtf/HashFunctions.h"
 #include "platform/wtf/HashTraits.h"
@@ -250,7 +249,8 @@ class Member : public MemberBase<T, TracenessMemberConfiguration::kTraced> {
 
  protected:
   ALWAYS_INLINE void WriteBarrier(const T* value) const {
-#if BUILDFLAG(BLINK_HEAP_INCREMENTAL_MARKING)
+// TODO(mlippautz): Replace with proper build flag.
+#if 0
     if (value) {
       // The following method for retrieving a page works as allocation of
       // mixins on large object pages is prohibited.
@@ -260,7 +260,7 @@ class Member : public MemberBase<T, TracenessMemberConfiguration::kTraced> {
         ThreadState::Current()->Heap().WriteBarrierInternal(page, value);
       }
     }
-#endif  // BUILDFLAG(BLINK_HEAP_INCREMENTAL_MARKING)
+#endif
   }
 };
 

third_party/WebKit/Source/platform/heap/ThreadState.cpp

@@ -44,7 +44,6 @@
 #include "platform/heap/Handle.h"
 #include "platform/heap/Heap.h"
 #include "platform/heap/HeapCompact.h"
-#include "platform/heap/IncrementalMarking.h"
 #include "platform/heap/PagePool.h"
 #include "platform/heap/SafePoint.h"
 #include "platform/heap/Visitor.h"
@@ -365,14 +364,15 @@ bool ThreadState::JudgeGCThreshold(size_t allocated_object_size_threshold,
 }
 
 bool ThreadState::ShouldScheduleIncrementalMarking() const {
-#if BUILDFLAG(BLINK_HEAP_INCREMENTAL_MARKING)
+// TODO(mlippautz): Replace with proper build flag.
+#if 0
   // TODO(mlippautz): For now immediately schedule incremental marking if
   // the runtime flag is provided, basically exercising a stress test.
   return (GcState() == kNoGCScheduled || GcState() == kSweeping) &&
          RuntimeEnabledFeatures::HeapIncrementalMarkingEnabled();
 #else
   return false;
-#endif  // BUILDFLAG(BLINK_HEAP_INCREMENTAL_MARKING)
+#endif
 }
 
 bool ThreadState::ShouldScheduleIdleGC() {