Revert "[api] Remove deprecated functions"

This reverts commit 5414884a.

Reason for revert: breaks the roll due to not testing CrOs

Original change's description:
> [api] Remove deprecated functions
> 
> Removes all V8_DEPRECATED functions that weren't recently marked as well
> any V8_DEPRECATE_SOON function that relied on using the address of
> an object to get hold of the Isolate.
> 
> Normally we would have advanced the V8_DEPRECATE_SOON methods to
> V8_DEPRECATE in this release and removed them in the follow release, but
> their continuing presence blocks the work on creating a shared
> Read-Only space where some objects would not belong to any single
> Isolate. In preparation chromium and node.js (via the v8/node github)
> have been modified in advance.
> 
> Bug: v8:7786
> Cq-Include-Trybots: luci.chromium.try:linux_chromium_rel_ng
> Change-Id: I8b4b06189896d94aff908ebcd121b3b38f9b482a
> Reviewed-on: https://chromium-review.googlesource.com/1154915
> Commit-Queue: Dan Elphick <delphick@chromium.org>
> Reviewed-by: Yang Guo <yangguo@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#54915}

TBR=yangguo@chromium.org,delphick@chromium.org

Change-Id: Iaf23e04d55a95b01b0423effa6cde3c0be5e2ba8
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:7786
Cq-Include-Trybots: luci.chromium.try:linux_chromium_rel_ng
Reviewed-on: https://chromium-review.googlesource.com/1164902Reviewed-by: Dan Elphick <delphick@chromium.org>
Commit-Queue: Dan Elphick <delphick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54937}

src/isolate.cc

@@ -2216,6 +2216,14 @@ void Isolate::SetAbortOnUncaughtExceptionCallback(
   abort_on_uncaught_exception_callback_ = callback;
 }
 
+Handle<Context> Isolate::GetCallingNativeContext() {
+  JavaScriptFrameIterator it(this);
+  if (it.done()) return Handle<Context>::null();
+  JavaScriptFrame* frame = it.frame();
+  Context* context = Context::cast(frame->context());
+  return Handle<Context>(context->native_context(), this);
+}
+
 Handle<Context> Isolate::GetIncumbentContext() {
   JavaScriptFrameIterator it(this);
 

src/isolate.h

@@ -868,6 +868,10 @@ class Isolate : private HiddenFactory {
   inline Handle<Context> native_context();
   inline Context* raw_native_context();
 
+  // Returns the native context of the calling JavaScript code.  That
+  // is, the native context of the top-most JavaScript frame.
+  Handle<Context> GetCallingNativeContext();
+
   Handle<Context> GetIncumbentContext();
 
   void RegisterTryCatchHandler(v8::TryCatch* that);
@@ -1783,6 +1787,9 @@ class Isolate : private HiddenFactory {
   friend class v8::Locker;
   friend class v8::SnapshotCreator;
   friend class v8::Unlocker;
+  friend v8::StartupData v8::V8::CreateSnapshotDataBlob(const char*);
+  friend v8::StartupData v8::V8::WarmUpSnapshotDataBlob(v8::StartupData,
+                                                        const char*);
 
   DISALLOW_COPY_AND_ASSIGN(Isolate);
 };