Revert 17963, 17962 and 17955: Random number generator in JS changes

src/v8.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 101 matching lines @@
 #endif
 }
 
 
 void V8::SetReturnAddressLocationResolver(
       ReturnAddressLocationResolver resolver) {
   StackFrame::SetReturnAddressLocationResolver(resolver);
 }
 
 
+// Used by JavaScript APIs
+uint32_t V8::Random(Context* context) {
+  ASSERT(context->IsNativeContext());
+  ByteArray* seed = context->random_seed();
+  uint32_t* state = reinterpret_cast<uint32_t*>(seed->GetDataStartAddress());
+
+  // When we get here, the RNG must have been initialized,
+  // see the Genesis constructor in file bootstrapper.cc.
+  ASSERT_NE(0, state[0]);
+  ASSERT_NE(0, state[1]);
+
+  // Mix the bits.  Never replaces state[i] with 0 if it is nonzero.
+  state[0] = 18273 * (state[0] & 0xFFFF) + (state[0] >> 16);
+  state[1] = 36969 * (state[1] & 0xFFFF) + (state[1] >> 16);
+
+  return (state[0] << 14) + (state[1] & 0x3FFFF);
+}
+
+
 void V8::AddCallCompletedCallback(CallCompletedCallback callback) {
   if (call_completed_callbacks_ == NULL) {  // Lazy init.
     call_completed_callbacks_ = new List<CallCompletedCallback>();
   }
   for (int i = 0; i < call_completed_callbacks_->length(); i++) {
     if (callback == call_completed_callbacks_->at(i)) return;
   }
   call_completed_callbacks_->Add(callback);
 }
 
@@ skipping 69 matching lines @@
   platform_ = NULL;
 }
 
 
 v8::Platform* V8::GetCurrentPlatform() {
   ASSERT(platform_);
   return platform_;
 }
 
 } }  // namespace v8::internal