Load v8 snapshots directly from APK (and store them uncompressed)

gin/v8_initializer.h

Index: gin/v8_initializer.h
diff --git a/gin/v8_initializer.h b/gin/v8_initializer.h
index 68068c4848b567a696ecaa1c028622df010fe990..d5b7ab4a13d42d3e3ee55a440c98ea56b821d36c 100644
--- a/gin/v8_initializer.h
+++ b/gin/v8_initializer.h
@@ -6,6 +6,7 @@
 #define GIN_V8_INITIALIZER_H_
 
 #include "base/files/file.h"
+#include "base/files/memory_mapped_file.h"
 #include "gin/array_buffer.h"
 #include "gin/gin_export.h"
 #include "gin/public/isolate_holder.h"
@@ -16,10 +17,6 @@ namespace gin {
 
 class GIN_EXPORT V8Initializer {
  public:
-  static const int kV8SnapshotBasePathKey;
-  static const char kNativesFileName[];
-  static const char kSnapshotFileName[];
-
   // This should be called by IsolateHolder::Initialize().
   static void Initialize(gin::IsolateHolder::ScriptMode mode);
 
@@ -31,7 +28,16 @@ class GIN_EXPORT V8Initializer {
                                         const char** snapshot_data_out,
                                         int* snapshot_size_out);
 
-#if defined(V8_USE_EXTERNAL_STARTUP_DATA)
+#if defined(OS_POSIX) && defined(V8_USE_EXTERNAL_STARTUP_DATA)
+
+  struct V8Files {
+    base::ScopedFD natives_fd;
+    base::ScopedFD snapshot_fd;
+    base::MemoryMappedFile::Region natives_region;
+    base::MemoryMappedFile::Region snapshot_region;
+   public:
+    bool IsLoaded() const;
+  };
 
   // Load V8 snapshot from user provided platform file descriptors.
   // The offset and size arguments, if non-zero, specify the portions
@@ -48,11 +54,9 @@ class GIN_EXPORT V8Initializer {
   // snapshot is already loaded, false otherwise.
   static bool LoadV8Snapshot();
 
-  // Opens the V8 snapshot data files and returns open file descriptors to these
-  // files in |natives_fd_out| and |snapshot_fd_out|, which can be passed to
-  // child processes.
-  static bool OpenV8FilesForChildProcesses(base::PlatformFile* natives_fd_out,
-                                           base::PlatformFile* snapshot_fd_out);
+  // Opens the V8 snapshot data files and returns open file descriptors and
+  // file regions to these files that can be passed to child processes.
+  static void OpenV8FilesForChildProcesses(V8Files* files_out);
 
 #endif  // V8_USE_EXTERNAL_STARTUP_DATA
 };