Strengthen is_official_build, update docs.

This makes is_official_build turn off all development targets and
features in Skia, including building third-party dependencies from
source.

This will intentionally break some external users, who will find
themselves no longer able to find third-party headers or link against
third-party libraries.  These users have been building with our testing
third-party dependencies unknowingly.  They'll need to either explicitly
turn back on building each dependency from source
(skia_use_system_foo=false) or disable that dependency entirely
(skia_use_foo=false).

is_skia_standalone is now basically !is_official_build, so I've
propagated that through, removing is_skia_standalone.  In a few places
we were using it as a stand-in for defined(ndk), so I've just written
defined(ndk) there.  Duh.

gn_to_bp:

    is_offical_build's new strength also makes gn_to_bp.py simpler to
    write.  In spirit, Android builds are official Skia builds that also
    build DM and nanobench.

    It seems that SkJumper (src/jumper/*) is (unintentionally) enabled
    on Android.  Switching to an is_official_build would have disabled
    that.  But as that accidental launch seems to have gone fine, I've
    kept it explicitly enabled.

    In the end, no changes to Android.bp or its SkUserConfig.h.

The -Mini builder no longer needs to explicitly disable tools.
CQ_INCLUDE_TRYBOTS=skia.primary:Build-Ubuntu-Clang-x86_64-Release-Mini

Change-Id: Id06e53268a5caf55c6046ada354a0863c3031c73
Reviewed-on: https://skia-review.googlesource.com/9190
Reviewed-by: Leon Scroggins <scroggo@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Mike Klein <mtklein@chromium.org>
diff --git a/BUILD.gn b/BUILD.gn
index b23277c..419b082 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -6,10 +6,6 @@
 import("gn/android_framework_defines.gni")
 import("gn/shared_sources.gni")
 
-if (!defined(is_skia_standalone)) {
-  is_skia_standalone = false
-}
-
 declare_args() {
   skia_use_angle = false
   skia_use_expat = true
@@ -29,11 +25,11 @@
   skia_enable_android_framework_defines = false
   skia_enable_discrete_gpu = true
   skia_enable_effects = true
-  skia_enable_jumper = is_skia_standalone
+  skia_enable_jumper = !is_official_build
   skia_enable_gpu = true
   skia_enable_pdf = true
-  skia_enable_tools = is_skia_standalone
-  skia_enable_vulkan_debug_layers = is_skia_standalone && is_debug
+  skia_enable_tools = !is_official_build
+  skia_enable_vulkan_debug_layers = !is_official_build && is_debug
   skia_vulkan_sdk = getenv("VULKAN_SDK")
 }
 declare_args() {
@@ -667,7 +663,7 @@
 
   if (is_android) {
     deps += [ "//third_party/expat" ]
-    if (is_skia_standalone && ndk != "") {
+    if (defined(ndk) && ndk != "") {
       deps += [ "//third_party/cpu-features" ]
     }
     sources += [ "src/ports/SkDebug_android.cpp" ]
@@ -1449,7 +1445,7 @@
     }
   }
 
-  if (is_android && is_skia_standalone && ndk != "") {
+  if (is_android && defined(ndk) && ndk != "") {
     copy("gdbserver") {
       sources = [
         "$ndk/$ndk_gdbserver",