Stubbed out linking on Fuchsia

Follows https://codereview.chromium.org/2931143002/. Sufficient to link
d8 with target_os="fuchsia" in Chrome. No implementations of platform
functions yet, just stubs.

BUG=chromium:731217

Review-Url: https://codereview.chromium.org/2932053004
Cr-Commit-Position: refs/heads/master@{#45832}

BUILD.gn

@@ -2597,6 +2597,11 @@ v8_component("v8_libbase") {
         "src/base/platform/platform-linux.cc",
       ]
     }
+  } else if (is_fuchsia) {
+    sources += [
+      "src/base/debug/stack_trace_fuchsia.cc",
+      "src/base/platform/platform-fuchsia.cc",
+    ]
   } else if (is_mac) {
     sources += [
       "src/base/debug/stack_trace_posix.cc",

src/base/debug/stack_trace_fuchsia.cc

+// Copyright 2017 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "src/base/debug/stack_trace.h"
+
+#include <iomanip>
+#include <ostream>
+
+#include "src/base/platform/platform.h"
+
+namespace v8 {
+namespace base {
+namespace debug {
+
+bool EnableInProcessStackDumping() {
+  CHECK(false);  // TODO(fuchsia): Port, https://crbug.com/731217.
+  return false;
+}
+
+void DisableSignalStackDump() {}
+
+StackTrace::StackTrace() {}
+
+void StackTrace::Print() const {
+  std::string backtrace = ToString();
+  OS::Print("%s\n", backtrace.c_str());
+}
+
+void StackTrace::OutputToStream(std::ostream* os) const {
+  for (size_t i = 0; i < count_; ++i) {
+    *os << "#" << std::setw(2) << i << trace_[i] << "\n";
+  }
+}
+
+}  // namespace debug
+}  // namespace base
+}  // namespace v8

src/base/platform/platform-fuchsia.cc

+// Copyright 2017 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "src/base/macros.h"
+#include "src/base/platform/platform-posix.h"
+#include "src/base/platform/platform.h"
+
+namespace v8 {
+namespace base {
+
+TimezoneCache* OS::CreateTimezoneCache() { return new PosixTimezoneCache(); }
+
+std::vector<OS::SharedLibraryAddress> OS::GetSharedLibraryAddresses() {
+  CHECK(false);  // TODO(fuchsia): Port, https://crbug.com/731217.
+  return std::vector<SharedLibraryAddress>();
+}
+
+void OS::SignalCodeMovingGC() {
+  CHECK(false);  // TODO(fuchsia): Port, https://crbug.com/731217.
+}
+
+VirtualMemory::VirtualMemory() : address_(NULL), size_(0) {}
+
+VirtualMemory::VirtualMemory(size_t size)
+    : address_(ReserveRegion(size)), size_(size) {
+  CHECK(false);  // TODO(fuchsia): Port, https://crbug.com/731217.
+}
+
+VirtualMemory::VirtualMemory(size_t size, size_t alignment)
+    : address_(NULL), size_(0) {}
+
+VirtualMemory::~VirtualMemory() {}
+
+bool VirtualMemory::IsReserved() { return false; }
+
+void VirtualMemory::Reset() {}
+
+bool VirtualMemory::Commit(void* address, size_t size, bool is_executable) {
+  return false;
+}
+
+bool VirtualMemory::Uncommit(void* address, size_t size) { return false; }
+
+bool VirtualMemory::Guard(void* address) { return false; }
+
+// static
+void* VirtualMemory::ReserveRegion(size_t size) {
+  CHECK(false);  // TODO(fuchsia): Port, https://crbug.com/731217.
+  return NULL;
+}
+
+// static
+bool VirtualMemory::CommitRegion(void* base, size_t size, bool is_executable) {
+  CHECK(false);  // TODO(fuchsia): Port, https://crbug.com/731217.
+  return false;
+}
+
+// static
+bool VirtualMemory::UncommitRegion(void* base, size_t size) {
+  CHECK(false);  // TODO(fuchsia): Port, https://crbug.com/731217.
+  return false;
+}
+
+// static
+bool VirtualMemory::ReleasePartialRegion(void* base, size_t size,
+                                         void* free_start, size_t free_size) {
+  CHECK(false);  // TODO(fuchsia): Port, https://crbug.com/731217.
+  return false;
+}
+
+// static
+bool VirtualMemory::ReleaseRegion(void* base, size_t size) {
+  CHECK(false);  // TODO(fuchsia): Port, https://crbug.com/731217.
+  return false;
+}
+
+// static
+bool VirtualMemory::HasLazyCommits() {
+  CHECK(false);  // TODO(fuchsia): Port, https://crbug.com/731217.
+  return false;
+}
+
+}  // namespace base
+}  // namespace v8

src/v8.gyp

@@ -2203,6 +2203,12 @@
             'base/platform/platform-posix.cc'
           ]},
         ],
+        ['OS=="fuchsia"', {
+          'sources': [
+            'base/debug/stack_trace_fuchsia.cc',
+            'base/platform/platform-fuchsia.cc',
+          ]},
+        ],
         ['OS=="solaris"', {
             'link_settings': {
               'libraries': [