From b407fc48cab419ba3966844652cbe4e44288f7a1 Mon Sep 17 00:00:00 2001
From: Chinmay Garde <chinmaygarde@google.com>
Date: Thu, 3 Mar 2016 12:00:24 -0800
Subject: [PATCH] Dont include any of the machinery to generate a
 precompilation snapshot on the embedder VM

---
 sky/build/SnapshotterInvoke         |  2 +-
 sky/engine/core/script/dart_init.cc | 27 +++++++++++++++++++--------
 sky/shell/BUILD.gn                  |  9 +++++++--
 3 files changed, 27 insertions(+), 11 deletions(-)

diff --git a/sky/build/SnapshotterInvoke b/sky/build/SnapshotterInvoke
index 0909015d6df..35f174ade92 100755
--- a/sky/build/SnapshotterInvoke
+++ b/sky/build/SnapshotterInvoke
@@ -126,7 +126,7 @@ SnapshotProject() {
   # Note about "checked mode": Precompilation snapshots are never in checked
   # mode. The flag is also ignored by the standalone VM. So there is no sense
   # in generating the larger snapshot. For development purposes, a
-  # non-precompilation enabled VM is used.
+  # non-precompilation-enabled VM is used.
   RunCommand ${FLUTTER_ARCH_TOOLS_PATH}/Snapshotter                            \
       --vm_isolate_snapshot=${derived_dir}/kDartVmIsolateSnapshotBuffer        \
       --isolate_snapshot=${derived_dir}/kDartIsolateSnapshotBuffer             \
diff --git a/sky/engine/core/script/dart_init.cc b/sky/engine/core/script/dart_init.cc
index dceac3bbd12..a4818ec98e2 100644
--- a/sky/engine/core/script/dart_init.cc
+++ b/sky/engine/core/script/dart_init.cc
@@ -66,10 +66,11 @@ Dart_Handle DartLibraryTagHandler(Dart_LibraryTag tag,
 
 namespace {
 
-static const char* kDartArgs[] = {
-    "--enable_mirrors=false",
+static const char* kDartProfilingArgs[] = {
+    // Dart assumes ARM devices are insufficiently powerful and sets the
+    // default profile period to 100Hz. This number is suitable for older
+    // Raspberry Pi devices but quite low for current smartphones.
     "--profile_period=1000",
-    "--background_compilation",
 #if (WTF_OS_IOS || WTF_OS_MACOSX)
     // On platforms where LLDB is the primary debugger, SIGPROF signals
     // overwhelm LLDB.
@@ -77,8 +78,12 @@ static const char* kDartArgs[] = {
 #endif
 };
 
-static const char* kDartPrecompilationArgs[]{
-    "--precompilation",
+static const char *kDartMirrorsArgs[] = {
+  "--enable_mirrors=false",
+};
+
+static const char* kDartBackgroundCompilationArgs[] = {
+  "--background_compilation",
 };
 
 static const char* kDartCheckedModeArgs[] = {
@@ -318,10 +323,16 @@ void InitDartVM() {
   }
 
   Vector<const char*> args;
-  args.append(kDartArgs, arraysize(kDartArgs));
+  args.append(kDartProfilingArgs, arraysize(kDartProfilingArgs));
 
-  if (IsRunningPrecompiledCode())
-    args.append(kDartPrecompilationArgs, arraysize(kDartPrecompilationArgs));
+  if (!IsRunningPrecompiledCode()) {
+    // The version of the VM setup to run precompiled code does not recognize
+    // the mirrors or the background compilation flags. They are never enabled.
+    // Make sure we dont pass in unrecognized flags.
+    args.append(kDartMirrorsArgs, arraysize(kDartMirrorsArgs));
+    args.append(kDartBackgroundCompilationArgs,
+                arraysize(kDartBackgroundCompilationArgs));
+  }
 
   if (enable_checked_mode)
     args.append(kDartCheckedModeArgs, arraysize(kDartCheckedModeArgs));
diff --git a/sky/shell/BUILD.gn b/sky/shell/BUILD.gn
index a558b408437..0dfc170a4d9 100644
--- a/sky/shell/BUILD.gn
+++ b/sky/shell/BUILD.gn
@@ -30,11 +30,16 @@ source_set("common") {
     "ui_delegate.h",
   ]
 
-  public_deps = [
+  if (is_ios && !use_ios_simulator) {
+    dart_deps = [ "//dart/runtime:libdart_precompiled_runtime" ]
+  } else {
+    dart_deps = [ "//dart/runtime:libdart" ]
+  }
+
+  public_deps = dart_deps + [
     "//base",
     "//base:i18n",
     "//build/config/sanitizers:deps",
-    "//dart/runtime:libdart",
     "//flow",
     "//mojo/common",
     "//mojo/data_pipe_utils",