Statically link libprotobuf_lite on Linux component builds

third_party/protobuf/BUILD.gn

Index: third_party/protobuf/BUILD.gn
diff --git a/third_party/protobuf/BUILD.gn b/third_party/protobuf/BUILD.gn
index 48a8f2395d140118f7eeac2bd33d6234a079b871..f7401c815076950559c1fe48248361ffd03fcd30 100644
--- a/third_party/protobuf/BUILD.gn
+++ b/third_party/protobuf/BUILD.gn
@@ -136,7 +136,32 @@ if (is_win) {
   ]
 }
 
-component("protobuf_lite") {
+# Do not allow libprotobuf_lite to be dynamically linked on Linux.  Later
+# versions of Ubuntu like Xenial and Yakkety link in the system
+# libprotobuf_lite by the following dependency chain: chrome -> gtk ->
+# libmirclient -> libmirprotobuf -> libprotobuf-lite.  Trying to load
+# the system libprotobuf-lite after already having loaded the libprotobuf_lite
+# component will result in an immediate crash. (crbug.com/700120)
+if (is_linux && !is_chromeos) {
+  link_target_type = "static_library"
+} else {
+  link_target_type = "component"
+}
+
+if (is_component_build && is_linux && !is_chromeos) {

[Peter Kasting, 2017/03/15 21:53:52]

Nit: This deserves a comment about what it's doing and why, and maybe how we'd
know if it were ever safe to remove this.

[Tom (Use chromium acct), 2017/03/19 07:19:11]

Done.

+  component("protobuf_globals") {
+    configs += [
+      ":protobuf_config",
+      ":protobuf_use_dlls",
+    ]
+    defines = [ "LIBPROTOBUF_EXPORTS" ]
+    sources = [
+      "src/google/protobuf/globals.cc",
+    ]
+  }
+}
+
+target(link_target_type, "protobuf_lite") {
   sources = protobuf_lite_sources
 
   configs -= [ "//build/config/compiler:chromium_code" ]
@@ -165,8 +190,14 @@ component("protobuf_lite") {
 
   cflags = protobuf_lite_cflags
 
+  if (is_component_build && is_linux && !is_chromeos) {
+    deps += [ ":protobuf_globals" ]
+  } else {
+    sources += [ "src/google/protobuf/globals.cc" ]
+  }
+
   # Required for component builds. See http://crbug.com/172800.
-  if (is_component_build) {
+  if (is_component_build && (!is_linux || is_chromeos)) {
     public_configs += [ ":protobuf_use_dlls" ]
     defines = [ "LIBPROTOBUF_EXPORTS" ]
   }
@@ -215,6 +246,7 @@ static_library("protobuf_full") {
     "src/google/protobuf/generated_enum_util.h",
     "src/google/protobuf/generated_message_reflection.cc",
     "src/google/protobuf/generated_message_reflection.h",
+    "src/google/protobuf/globals.cc",
 
     # gzip_stream.cc pulls in zlib, but it's not actually used by protoc, just
     # by test code, so instead of compiling zlib for the host, let's just