Blink Scheduler: Move common converter to tracing helper.

Follow-up for that CL:
https://chromium-review.googlesource.com/803797

So we shouldn't re-declare common function in different places
since it breaks jumbo build (where multiple .cc files get merged).

Change-Id: I68a3a75ca31a373557f3bb8106140828eae23da6
Reviewed-on: https://chromium-review.googlesource.com/811084Reviewed-by: Sami Kyöstilä <skyostil@chromium.org>
Commit-Queue: Greg Kraynov <kraynov@chromium.org>
Cr-Commit-Position: refs/heads/master@{#522135}

third_party/WebKit/Source/platform/scheduler/renderer/cpu_time_budget_pool.cc

@@ -19,11 +19,10 @@ CPUTimeBudgetPool::CPUTimeBudgetPool(
     BudgetPoolController* budget_pool_controller,
     base::TimeTicks now)
     : BudgetPool(name, budget_pool_controller),
-      current_budget_level_(
-          base::TimeDelta(),
-          "RendererScheduler.BackgroundBudgetMs",
-          budget_pool_controller,
-          [](const base::TimeDelta& value) { return value.InMillisecondsF(); }),
+      current_budget_level_(base::TimeDelta(),
+                            "RendererScheduler.BackgroundBudgetMs",
+                            budget_pool_controller,
+                            TimeDeltaToMilliseconds),
       last_checkpoint_(now),
       cpu_percentage_(1) {}
 

third_party/WebKit/Source/platform/scheduler/renderer/renderer_scheduler_impl.cc

@@ -93,10 +93,6 @@ const char* YesNoStateToString(bool is_yes) {
   }
 }
 
-double TimeDeltaToMilliseconds(const base::TimeDelta& value) {
-  return value.InMillisecondsF();
-}
-
 }  // namespace
 
 RendererSchedulerImpl::RendererSchedulerImpl(

third_party/WebKit/Source/platform/scheduler/util/tracing_helper.cc

@@ -57,5 +57,9 @@ std::string PointerToString(const void* pointer) {
       static_cast<uint64_t>(reinterpret_cast<uintptr_t>(pointer)));
 }
 
+double TimeDeltaToMilliseconds(const base::TimeDelta& value) {
+  return value.InMillisecondsF();
+}
+
 }  // namespace scheduler
 }  // namespace blink

third_party/WebKit/Source/platform/scheduler/util/tracing_helper.h

@@ -7,6 +7,7 @@
 
 #include <string>
 #include "base/macros.h"
+#include "base/time/time.h"
 #include "base/trace_event/trace_event.h"
 #include "platform/PlatformExport.h"
 
@@ -32,6 +33,8 @@ PLATFORM_EXPORT bool AreVerboseSnapshotsEnabled();
 
 PLATFORM_EXPORT std::string PointerToString(const void* pointer);
 
+PLATFORM_EXPORT double TimeDeltaToMilliseconds(const base::TimeDelta& value);
+
 // TRACE_EVENT macros define static variable to cache a pointer to the state
 // of category. Hence, we need distinct version for each category in order to
 // prevent unintended leak of state.