Webkit: keep minimal symbols when remove_webcore_debug_symbols is set.

We want to keep minimal symbols when remove_webcore_debug_symbols is
set, so that we can get readable backtrace.

On ChromeOS arm build, the size of debug file increases from
899MB to 1.244GB. It increases 245 MB.

Bug: chromium:792999
Change-Id: Ibc238308754a2727505cfbac3ce24f7a70027529
Reviewed-on: https://chromium-review.googlesource.com/862607Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Ryo Hashimoto <hashimoto@chromium.org>
Commit-Queue: Yunlian Jiang <yunlian@chromium.org>
Cr-Commit-Position: refs/heads/master@{#532545}

third_party/WebKit/Source/config.gni

@@ -14,10 +14,23 @@ if (current_cpu == "arm") {
 }
 
 declare_args() {
+  # TODO: send a PSA out to tell people to switch to blink_symbol_level
+  # and remove this.
   # If true, doesn't compile debug symbols into webcore reducing the
   # size of the binary and increasing the speed of gdb.
   remove_webcore_debug_symbols = false
 
+  # How many symbols to include in the build of blink. This affects
+  # the performance of the build since the symbols are large and dealing with
+  # them is slow.
+  #   2 means regular build with symbols.
+  #   1 means minimal symbols, usually enough for backtraces only. Symbols with
+  # internal linkage (static functions or those in anonymous namespaces) may not
+  # appear when using this level.
+  #   0 means no symbols.
+  #   -1 means auto-set according to debug/release and platform.
+  blink_symbol_level = -1
+
   # If true, defaults image interpolation to low quality.
   use_low_quality_image_interpolation = is_android
 
@@ -63,6 +76,9 @@ if (use_default_render_theme) {
   feature_defines_list += [ "WTF_USE_DEFAULT_RENDER_THEME=1" ]
 }
 
+assert(blink_symbol_level == -1 || !remove_webcore_debug_symbols,
+       "blink_symbol_level and remove_webcore_debug_symbols cannot both be set.")
+
 if (remove_webcore_debug_symbols) {
   if (is_win && symbol_level != 0) {
     # If we use no_symbols on Windows when symbol_level is not zero then no
@@ -71,9 +87,18 @@ if (remove_webcore_debug_symbols) {
     # situation keeps the build times fast (roughly identical to no_symbols)
     # while still generating a PDB to keep ninja happy (and it gives us proper
     # call stacks).
-    remove_webcore_symbols_config =
-        [ "//build/config/compiler:minimal_symbols" ]
+    blink_symbol_level = 1
   } else {
-    remove_webcore_symbols_config = [ "//build/config/compiler:no_symbols" ]
+    blink_symbol_level = 0
   }
 }
+
+if (blink_symbol_level == 2) {
+  blink_symbols_config = [ "//build/config/compiler:full_symbols" ]
+} else if (blink_symbol_level == 1) {
+  blink_symbols_config = [ "//build/config/compiler:minimal_symbols" ]
+} else if (blink_symbol_level == 0) {
+  blink_symbols_config = [ "//build/config/compiler:no_symbols" ]
+} else {
+  blink_symbols_config = [ "//build/config/compiler:default_symbols" ]
+}

third_party/WebKit/Source/controller/BUILD.gn

@@ -50,10 +50,8 @@ component("controller") {
     ]
   }
 
-  if (remove_webcore_debug_symbols) {
-    configs -= [ "//build/config/compiler:default_symbols" ]
-    configs += remove_webcore_symbols_config
-  }
+  configs -= [ "//build/config/compiler:default_symbols" ]
+  configs += blink_symbols_config
 }
 
 group("webkit_unit_tests_data") {

third_party/WebKit/Source/core/core.gni

@@ -30,10 +30,8 @@ if (is_win && is_official_build) {
   core_config_add += [ "//build/config/compiler:optimize_max" ]
 }
 
-if (remove_webcore_debug_symbols) {
-  core_config_remove += [ "//build/config/compiler:default_symbols" ]
-  core_config_add += remove_webcore_symbols_config
-}
+core_config_remove += [ "//build/config/compiler:default_symbols" ]
+core_config_add += blink_symbols_config
 
 # Use this target type to link core targets.
 if (is_component_build) {

third_party/WebKit/Source/modules/BUILD.gn

@@ -168,10 +168,8 @@ target("jumbo_" + modules_target_type, "modules") {
     cflags = [ "/wd4334" ]  # Result of 32-bit shift implicitly converted to 64 bits.
   }
 
-  if (remove_webcore_debug_symbols) {
-    configs -= [ "//build/config/compiler:default_symbols" ]
-    configs += remove_webcore_symbols_config
-  }
+  configs -= [ "//build/config/compiler:default_symbols" ]
+  configs += blink_symbols_config
 }
 
 jumbo_source_set("modules_testing") {

third_party/WebKit/Source/modules/modules.gni

@@ -71,8 +71,6 @@ set_defaults("blink_modules_sources") {
     "//third_party/WebKit/Source:non_test_config",
     "//third_party/WebKit/Source:inside_blink",
   ]
-  if (remove_webcore_debug_symbols) {
-    configs -= [ "//build/config/compiler:default_symbols" ]
-    configs += remove_webcore_symbols_config
-  }
+  configs -= [ "//build/config/compiler:default_symbols" ]
+  configs += blink_symbols_config
 }

third_party/WebKit/Source/platform/BUILD.gn

@@ -1674,10 +1674,8 @@ jumbo_component("platform") {
     deps += [ "//third_party/openmax_dl/dl" ]
   }
 
-  if (remove_webcore_debug_symbols) {
-    configs -= [ "//build/config/compiler:default_symbols" ]
-    configs += remove_webcore_symbols_config
-  }
+  configs -= [ "//build/config/compiler:default_symbols" ]
+  configs += blink_symbols_config
 }
 
 jumbo_static_library("test_support") {

third_party/WebKit/Source/platform/wtf/BUILD.gn

@@ -311,10 +311,8 @@ jumbo_component("wtf") {
     ]
   }
 
-  if (remove_webcore_debug_symbols) {
-    configs -= [ "//build/config/compiler:default_symbols" ]
-    configs += remove_webcore_symbols_config
-  }
+  configs -= [ "//build/config/compiler:default_symbols" ]
+  configs += blink_symbols_config
 }
 
 test("wtf_unittests") {