Enable loading native libraries with RTLD_DEEPBIND

base/BUILD.gn

Index: base/BUILD.gn
diff --git a/base/BUILD.gn b/base/BUILD.gn
index 12d6d7c7a35114408ccccfb95e045848624de796..d7f1cfc5716cc69c4d35187b9d0f6093cdbdf6d4 100644
--- a/base/BUILD.gn
+++ b/base/BUILD.gn
@@ -555,6 +555,7 @@ component("base") {
     "metrics/user_metrics.cc",
     "metrics/user_metrics.h",
     "metrics/user_metrics_action.h",
+    "native_library.cc",
     "native_library.h",
     "native_library_ios.mm",
     "native_library_mac.mm",
@@ -1057,6 +1058,10 @@ component("base") {
     public_deps += [ "//base/allocator:unified_allocator_shim" ]
   }
 
+  if (use_gold && !is_android) {

[Primiano Tucci (use gerrit), 2016/08/24 22:14:08]

why use_gold? The linker used to build the binary shouldn't make a different.
the behavior is given by the loader, not the linker (unless there is some gold
feature I'm not considering). 
IMHO this should be if (is_linux).
But at this point you don't need the define and you can just use #if
defined(OS_LINUX)

[Ken Rockot(use gerrit already), 2016/08/24 23:23:57]

Well, this was failing on cast_shell_linux, and the only relevant difference I
could find between is_chromecast true/false is that we don't use gold for
is_chromecast=true. In that configuration, we don't see the default global
behavior.

+    defines += [ "EXPECT_GLOBAL_RTLD_BEHAVIOR" ]

[Primiano Tucci (use gerrit), 2016/08/24 22:14:09]

adding defines to an entire target is discouraged, see brett's thread
[chromium-dev] New system for feature enable/disable flags [1]
If you really want this define, you need to use a buildflag_header here. See
allocator:features in base/allocator/BUILD.gn as an example [2]


[1]
https://groups.google.com/a/chromium.org/d/msg/chromium-dev/5c4ySpPsV14/JJfAe...
[2]
https://cs.chromium.org/chromium/src/base/allocator/BUILD.gn?q=allocator+feat...

[Ken Rockot(use gerrit already), 2016/08/24 23:23:57]

Oops. This was meant to be only on the base_unittests target (fixed). Is it more
palatable there given that it's a leaf target?

+  }
+
   # Allow more direct string conversions on platforms with native utf8
   # strings
   if (is_mac || is_ios || is_chromeos || is_chromecast) {
@@ -1135,6 +1140,7 @@ component("base") {
       "memory/discardable_shared_memory.cc",
       "memory/discardable_shared_memory.h",
       "memory/shared_memory_posix.cc",
+      "native_library.cc",
       "native_library_posix.cc",
       "path_service.cc",
       "process/kill.cc",
@@ -2027,6 +2033,10 @@ test("base_unittests") {
     "//third_party/icu",
   ]
 
+  data_deps = [
+    ":native_library_test_library",
+  ]
+
   if (is_ios || is_mac) {
     deps += [ ":base_unittests_arc" ]
   }
@@ -2153,6 +2163,12 @@ test("base_unittests") {
   }
 }
 
+shared_library("native_library_test_library") {
+  sources = [
+    "native_library_test_library.cc",
+  ]
+}
+
 action("build_date") {
   script = "//build/write_build_date_header.py"