Switch the Linux minidump writer to use MDCVInfoELF for CV data.

src/client/linux/minidump_writer/linux_ptrace_dumper_unittest.cc

Index: src/client/linux/minidump_writer/linux_ptrace_dumper_unittest.cc
diff --git a/src/client/linux/minidump_writer/linux_ptrace_dumper_unittest.cc b/src/client/linux/minidump_writer/linux_ptrace_dumper_unittest.cc
index 838ea5f6bacd860cb080bf2a63fba1f4e74e0ad9..d4439da768f6ea6a2f267a632f264ef7e3769f1c 100644
--- a/src/client/linux/minidump_writer/linux_ptrace_dumper_unittest.cc
+++ b/src/client/linux/minidump_writer/linux_ptrace_dumper_unittest.cc
@@ -310,12 +310,14 @@ TEST_F(LinuxPtraceDumperChildTest, LinuxGateMappingID) {
 
   // Need to suspend the child so ptrace actually works.
   ASSERT_TRUE(dumper.ThreadsSuspend());
-  uint8_t identifier[sizeof(MDGUID)];
+  uint8_t identifier[kMaxBuildID];
+  size_t identifier_length;
   ASSERT_TRUE(dumper.ElfFileIdentifierForMapping(*mappings[index],
                                                  true,
                                                  index,
-                                                 identifier));
-  uint8_t empty_identifier[sizeof(MDGUID)];
+                                                 identifier,
+                                                 &identifier_length));
+  uint8_t empty_identifier[kMaxBuildID];
   memset(empty_identifier, 0, sizeof(empty_identifier));
   EXPECT_NE(0, memcmp(empty_identifier, identifier, sizeof(identifier)));
   EXPECT_TRUE(dumper.ThreadsResume());
@@ -343,12 +345,15 @@ TEST_F(LinuxPtraceDumperChildTest, FileIDsMatch) {
   }
   ASSERT_TRUE(found_exe);
 
-  uint8_t identifier1[sizeof(MDGUID)];
-  uint8_t identifier2[sizeof(MDGUID)];
+  uint8_t identifier1[kMaxBuildID];
+  size_t identifier1_length;
+  uint8_t identifier2[kMaxBuildID];
+  size_t identifier2_length;
   EXPECT_TRUE(dumper.ElfFileIdentifierForMapping(*mappings[i], true, i,
-                                                 identifier1));
+                                                 identifier1,
+                                                 &identifier1_length));
   FileID fileid(exe_name);
-  EXPECT_TRUE(fileid.ElfFileIdentifier(identifier2));
+  EXPECT_TRUE(fileid.ElfFileIdentifier(identifier2, &identifier2_length));
   char identifier_string1[37];
   char identifier_string2[37];
   FileID::ConvertIdentifierToString(identifier1, identifier_string1,