Fix leaked array buffer allocators of isolates

The array buffer allocators are allocated and owned by pdfium code,
they should be deleted properly after the corresponding isolates are
disposed.

BUG=pdfium:242

Review-Url: https://codereview.chromium.org/2254123004
diff --git a/fxjs/cfxjse_isolatetracker.cpp b/fxjs/cfxjse_isolatetracker.cpp
index 9594df3..adf6f2a 100644
--- a/fxjs/cfxjse_isolatetracker.cpp
+++ b/fxjs/cfxjse_isolatetracker.cpp
@@ -12,8 +12,11 @@
 
 CFXJSE_IsolateTracker::~CFXJSE_IsolateTracker() {}
 
-void CFXJSE_IsolateTracker::Append(v8::Isolate* pIsolate) {
+void CFXJSE_IsolateTracker::Append(
+    v8::Isolate* pIsolate,
+    std::unique_ptr<v8::ArrayBuffer::Allocator> alloc) {
   m_OwnedIsolates.push_back(pIsolate);
+  m_AllocatorMap[pIsolate] = std::move(alloc);
 }
 
 void CFXJSE_IsolateTracker::Remove(
@@ -24,6 +27,8 @@
   if (bFound)
     m_OwnedIsolates.erase(it);
   lpfnDisposeCallback(pIsolate, bFound);
+
+  m_AllocatorMap.erase(pIsolate);
 }
 
 void CFXJSE_IsolateTracker::RemoveAll(
@@ -32,4 +37,5 @@
     lpfnDisposeCallback(pIsolate, true);
 
   m_OwnedIsolates.clear();
+  m_AllocatorMap.clear();
 }
diff --git a/fxjs/cfxjse_isolatetracker.h b/fxjs/cfxjse_isolatetracker.h
index 7558416..5340d9b 100644
--- a/fxjs/cfxjse_isolatetracker.h
+++ b/fxjs/cfxjse_isolatetracker.h
@@ -7,6 +7,8 @@
 #ifndef FXJS_CFXJSE_ISOLATETRACKER_H_
 #define FXJS_CFXJSE_ISOLATETRACKER_H_
 
+#include <map>
+#include <memory>
 #include <vector>
 
 #include "v8/include/v8.h"
@@ -57,7 +59,8 @@
   CFXJSE_IsolateTracker();
   ~CFXJSE_IsolateTracker();
 
-  void Append(v8::Isolate* pIsolate);
+  void Append(v8::Isolate* pIsolate,
+              std::unique_ptr<v8::ArrayBuffer::Allocator> alloc);
   void Remove(v8::Isolate* pIsolate, DisposeCallback lpfnDisposeCallback);
   void RemoveAll(DisposeCallback lpfnDisposeCallback);
 
@@ -65,6 +68,8 @@
 
  protected:
   std::vector<v8::Isolate*> m_OwnedIsolates;
+  std::map<v8::Isolate*, std::unique_ptr<v8::ArrayBuffer::Allocator>>
+      m_AllocatorMap;
 };
 
 #endif  // FXJS_CFXJSE_ISOLATETRACKER_H_
diff --git a/fxjs/cfxjse_runtimedata.cpp b/fxjs/cfxjse_runtimedata.cpp
index b203cb7..2c93795 100644
--- a/fxjs/cfxjse_runtimedata.cpp
+++ b/fxjs/cfxjse_runtimedata.cpp
@@ -56,11 +56,13 @@
 }
 
 v8::Isolate* FXJSE_Runtime_Create_Own() {
+  std::unique_ptr<v8::ArrayBuffer::Allocator> allocator(
+      new FXJSE_ArrayBufferAllocator());
   v8::Isolate::CreateParams params;
-  params.array_buffer_allocator = new FXJSE_ArrayBufferAllocator();
+  params.array_buffer_allocator = allocator.get();
   v8::Isolate* pIsolate = v8::Isolate::New(params);
   ASSERT(pIsolate && CFXJSE_IsolateTracker::g_pInstance);
-  CFXJSE_IsolateTracker::g_pInstance->Append(pIsolate);
+  CFXJSE_IsolateTracker::g_pInstance->Append(pIsolate, std::move(allocator));
   return pIsolate;
 }