Make blink/modules support jumbo compilations (-60 CPU minutes)

Compiling browser code in blink/modules currently use
about 80 CPU minutes. That is about 7% of the total compilation time.
If you use jumbo compilation (merge many files into a single
translation unit) that time drops to about a fifth of that.

There are also unit_tests in modules that will be jumbofied in
a different patch.

Bug: 713137
Change-Id: I9155d2af0c9dce6b3178f77b9366062eb45d4560
Reviewed-on: https://chromium-review.googlesource.com/568302Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Daniel Bratell <bratell@opera.com>
Cr-Commit-Position: refs/heads/master@{#488179}

third_party/WebKit/Source/modules/BUILD.gn

@@ -43,7 +43,7 @@ make_names("module_names") {
   deps = []  # Don't use default deps (otherwise it will be circular).
 }
 
-target(modules_target_type, "modules") {
+target("jumbo_" + modules_target_type, "modules") {
   output_name = "blink_modules"
 
   if (modules_target_type == "split_static_library") {

third_party/WebKit/Source/modules/fetch/BUILD.gn

@@ -43,4 +43,12 @@ blink_modules_sources("fetch") {
     "Response.cpp",
     "Response.h",
   ]
+
+  if (is_win && is_component_build) {
+    # Body.cpp exports a class (MODULES_EXPORT) that inherits from
+    # PairIterable<String, String> that is also used as base class by an
+    # imported (CORE_EXPORT) class and that confuses the Windows
+    # linker/compiler. https://crbug.com/739340
+    jumbo_excluded_sources = [ "Body.cpp" ]
+  }
 }

third_party/WebKit/Source/modules/modules.gni

@@ -7,9 +7,12 @@
 # This file is shared with all modules' BUILD files which shouldn't need access
 # to the huge and slow lists of sources. If sharing is necessary, make a
 # separate .gni.
+import("//build/config/jumbo.gni")
 import("//build/split_static_library.gni")
 import("//third_party/WebKit/Source/config.gni")
 
+blink_modules_output_dir = "$root_gen_dir/blink/modules"
+
 # Defines a part of blink modules. This is either a source set or a static
 # library with defaults for commonly-used values.
 #
@@ -29,7 +32,7 @@ template("blink_modules_sources") {
     }
   }
 
-  target(target_type, target_name) {
+  target("jumbo_" + target_type, target_name) {
     # The visibility will get overridden by forward_variables_from below if the
     # invoker defined it.
     visibility = [ "//third_party/WebKit/Source/modules/*" ]

third_party/WebKit/Source/modules/webaudio/BUILD.gn

@@ -125,6 +125,14 @@ blink_modules_sources("webaudio") {
   ]
 
   if (is_win) {
+    jumbo_excluded_sources = [
+      # Uses Supplement<LocalDOMWindow> with MODULES_EXPORT while
+      # other files use Supplement<LocalDOMWindow> with
+      # CORE_EXPORT. Mixing those in the same compilation unit
+      # triggers link errors in Windows. https://crbug.com/739340
+      "WindowAudioWorklet.cpp",
+    ]
+
     # Result of 32-bit shift implicitly converted to 64 bits.
     cflags = [ "/wd4334" ]
   }